Technical service bulletins are instructions a manufacturer sent its dealers about a known fault. They are not recalls and the work is usually not free, but they are the clearest signal of a problem the manufacturer already knows about.
LI46.35-P-067339
Service Bulletin/Repair Instructions
Complaint During part of the steering movement, it feels heavier or more difficult to steer in the same spot every time. OR Rattling, humming, dry sliding/gravel noise from the electric steering system when steering (see attachment). Complaint does not impact the ability to safely steer or control the vehicle. Cause Ball screw drive (KGT) of electric steering damaged by: 1. External force due to: ‑ Hitting the curb/posts with the front wheels. ‑ Driving over obstacles (e.g. pothole/ threshold/ speed bump/ gully) at an inappropriate speed. 2. Corrosion/ water ingress through a damaged boot (see attachment). ‑ Cracks (1) ‑ High pressure cleaner (2) ‑ Animal bite (3) See various examples listed in the attachments for examples of outside influence. Remedy Remove boot clamps closest to steering gear housing on both left and right (as seen in "Steering Rack Boot Clamp Location"). Pull back boot and inspect for rust, broken end stops, water, or any other anomalies. Replace electric steering. Note: Steering gears replaced due to outside influence or damage must not be claimed under warranty!
LI72.20-P-075746
Service Bulletin/Repair Instructions
Complaint Tailgate opens unintentionally. Cause Accidental or unnoticed activation of the button to open the tailgate on the vehicle key. EXAMPLE: when stored in trouser pocket, handbag etc. Remedy As of the 6th generation, the vehicle key can be recoded so that the tailgate no longer opens as a result of a long press on the button, but by double‑clicking on the button instead. This reduces the likelihood of the button being activated accidentally or unintentionally. The recoding can be carried out as follows: 1. Add SA Code O19 into VeDoc (O for Oscar, not "zero") • an XSS ticket may be necessary to add the SA code 2. Perform SCN coding of EIS N73 control unit 3. Deactivate the vehicle key (a successful deactivation is indicated by the LED lighting up 2x briefly and then 1x for a long period). 4. Place the vehicle key in the storage compartment on the key symbol and turn on the ignition. IMPORTANT: all other vehicle keys must be outside the recognition range of the vehicle when doing this! Perform steps 3 and 4 successively for all vehicle keys. Notes: 6th, 7th and 8th generation keys can be deactivated as follows: Up to modification year 22/1 by double clicking the "Lock button" As of modification year 22/1, by press and holding the “Lock button", then double‑click the “Unlock button" at the same time. On model series 167, the storage compartment with the key symbol is located in the armrest. The SCN coding from the EZS is only transferred correctly to the vehicle key under the following conditions: Only one vehicle key is located in the vehicle, this key has been deactivated and it is positioned on the marking in the storage compartment for the data transfer. The costs for this adaptation are to be borne by the customer. For the newer BR 174, 178, 244, 248, 520, and 540, a software update must be initiated, as there is no way to perform SCN coding.
LI54.71-P-079104
Service Bulletin/Repair Instructions
Complaint Traffic sign symbol for "Traffic Sign Assist" is blinking in instrument cluster without obvious cause usually with one of the following scenarios: • Flashing without a speed limit ("‑ ‑"). • Flashing when current vehicle speed is under speed limit. • Flashing between US speed limit symbol and European speed limit symbol. NOTE: • Verify that the concern falls under one of the attachment videos. If not, then it is outside of the scope of this LI. • This also does not cover "Traffic Sign Inoperative" messages on the instrument cluster. Cause There are two identified reasons for this concern: 1. Country code information stored incorrectly at a particular geographic latitude range. 2. Incorrect reference data when the vehicle is started and a GPS signal is not immediately available. Remedy Update head unit software to latest version and the re‑check function in the same location. If vehicle is still exhibiting one of the symptoms as described exactly as in the complaint section or as shown in the video attachments, open a TIPS case to the Body/Chassis/Entertainment inbox with the following: • Video of the concern. • Exact location (latitude and longitude is best)
LI72.00-P-080885
Service Bulletin/Repair Instructions
Complaint The Dark Chrome finish on the retractable door handle appears discolored, stained, or faded. The discoloration is typically visible along the upper surface of the handle. Cause Insufficient surface treatment of the black chrome from the supplier Remedy 1.) Clean door handles. 2.) Inspect the handle after cleaning. • Confirm that the discoloration remains clearly visible across the upper portion of the handle. • Compare the condition to the LI reference photos 3.) If the discoloration matches the fault profile shown in the reference photos → replace the affected retractable door handle.
LI82.85-P-079088
Service Bulletin/Repair Instructions
Complaint The following most common complaints may be observed: • Brief connectivity interruptions when using Apple CarPlay over Wi-Fi • Audio cuts out • Device not recognized • No operation possible Cause There are multiple possible causes for an iPhone disconnecting from a vehicle’s head unit while using Apple CarPlay. These include hardware, software, and environmental factors: Environmental Interference External Sources: • Passing under toll bridges, driving near airports, or areas with heavy electronic interference (e.g., as described in LI82.85-P-076157) can cause connection drops. Cellular Networks: • Interference from nearby cell towers operating on similar frequencies (usually 2.4GHz or 5GHz) can disrupt the signal. Storage Location: • Keeping your phone in a handbag or surrounded by other objects inside the vehicle can create physical or electronic interference. Device and Software Issues Head Unit Software/Hardware: • Outdated firmware, bugs, or hardware faults in the vehicle’s head unit can prevent a stable connection. iPhone Software/Hardware: • Similar issues in the iPhone, including buggy iOS updates or hardware problems, may affect performance. Reset or Reboot:• Automatic rebooting or resetting of either the head unit or the iPhone will temporarily disrupt CarPlay. Connection and Settings Wired Connections: • Faulty Cable: A damaged or poor-quality USB cable can cause intermittent or total loss of connection. • USB Port Issues: Dust, debris, or physical damage in the USB port of either the head unit or the iPhone can also lead to disconnects. Wireless Connections: • Intermittent Bluetooth/Wi-Fi: Unstable wireless communication (Bluetooth/Wi-Fi) can frequently break the Car- Play connection. Power Management: • Battery Saver Mode: Enabling low power mode may restrict background processes, affecting CarPlay. • Vehicle’s Electrical System: Unstable power delivery from the car’s battery or electrical interruptions can cause the head unit to malfunction. Phone & App Configuration Phone Settings: • Incorrect or conflicting settings (especially Bluetooth or Wi-Fi) on your iPhone can interfere with the CarPlay link. • Third-Party Apps/Profiles: • Installed apps or configuration profiles may conflict with CarPlay’s operation. • Native apps are apple maps, apple music, audio books, apple news, podcasts, messages and phone. All other apps are considered third party apps. App Conflicts: • Running conflicting apps that require similar system resources as CarPlay can cause instability. Mobile Data Plan: • Streaming from online sources without sufficient mobile data can result in lost connectivity. Other Factors Heat & Overheating: • If either the phone or the head unit overheats, they may disable certain functions to prevent damage, leading to disconnection. User Actions: • Accidentally disconnecting the device in settings, or physically moving or bumping the phone or cable, may disrupt the connection. Remedy FUP6 (E605.8) software has been released for the following chassis: 118, 177, 243,247,206,254,167,294,295,296,223, 297. Flash available software for the head unit and test for function. The LI will be updated once available for the remaining chassis. If the complaint remains after the SW update please continue with the steps below. Guided Diagnostic Path for Apple CarPlay Connection Issues: Please follow the steps below to systematically diagnose and resolve CarPlay concerns:Update Devices: • Ensure the iPhone is updated to the latest available iOS version. • Ensure the vehicle’s head unit is updated to the latest software version available. Isolate the Issue: • Check whether the symptom persists with another iPhone running the latest iOS version. • Test both wireless and wired CarPlay connections: • Does the issue only occur with wireless CarPlay? • Does the wired connection to the phone function correctly? Further Troubleshooting Steps: • Reboot the iPhone. See attachment for further instructions.
LI01.20-P-080884
Service Bulletin/Repair Instructions
Complaint Oil leaks found on M176 or M177 engines diagnosed to be from the cylinder head cover area Cause Unknown (under investigation) Remedy If oil leaks are found at left or right cylinder head cover area please collect the following information and open TIPS case. 1. Collect photos of the leak 2. Include close up and wide view photos to accurately represent the location 3. Include if the vehicle has a "check oil level" Light on in the cluster or fault codes 4. Check oil level as per WIS to verify level and calculate possible oil loss from the leak 5. Identify and communicate the severity of the leak and provide supporting documentation 6. Open a TIPS case with the above information and submit to the Powertrain team for processing
LI54.65-P-080132
Service Bulletin/Repair Instructions
Complaint 1. General Diagnostic Tips 2. One or More PARK Sensor Activations 3. Red Ring Around Vehicle 4. "Active Parking and Parking Assist Inoperative" on Instrument Cluster 5. Cameras 6. Other Park Topics. Cause Various root causes Remedy See attached diagnostic guide.
LI82.62-P-078631
Service Bulletin/Repair Instructions
Complaint Clanking noise from the area of the speakers in the doors. Cause Under analysis. Remedy To narrow down the cause, first of all remove the door trim. • If the noise continues to occur even with the door trim removed, then continue the diagnosis working towards the speaker and if necessary, create a TIPS case with an informative video as an attachment. Information: Please refer to this document in the warranty claim and, after completing diagnosis, select the damage code corresponding to the component part that caused the problem. • If the noise stops when the door trim is removed, please proceed in accordance with LI72.10-P-067691. Information: In this case, do not use a damage code for the speakers in the warranty claim!
LI27.00-P-075630
Service Bulletin/Repair Instructions
Complaint This document is intended as a pre-case diagnostic reference for transmission related concerns. It will also ensure that if a case is necessary, all supporting documentation is available. This should not be used on its own as justification for creating a TIPS case. Cause The root cause will vary depending on the complaint. The goal of this document is to provide diagnostic checks and procedures that may help resolve customer complaints without opening a TIPS case. Remedy Before opening a transmission-related TIPS case, the following steps must be performed to ensure all relevant data has been collected and possible remedies (when applicable) have been performed. Please Note: At minimum, the documents below must be collected before proceeding to ensure the data in its original state when the vehicle arrived is captured. - Initial Quick Test w/ Freeze frame data - VGS Control Unit Log - Initial EEPROM data (.txt format) - IPR Result (if applicable. See LI27.00-P-073124 - Transmission diagnosis using the Intelligent Predictive Repair (IPR) tool) - Transmission Heath Page If the vehicle has previously been repaired for the same concern, note the date, mileage, and TIPS case or RO number, along with a brief description of the prior work performed. IPR Guidance: The IPR recommended repair should be completed prior to following any steps in this LI and prior to case creation. IPR repairs do not require additional warranty approvals or a TIPS case to validate/confirm the results. To ensure efficient case handling, please avoid opening TIPS cases for this reason. For further information regarding IPR please see the following documents: LI27.00-P-073124 - Transmission diagnosis using the Intelligent Predictive Repair (IPR) tool Oil Pan Condition Evaluation: In some situations, IPR will advise checking the oil pan condition and determining a repair based on the evaluation. Example photos in Xentry can be found in two ways: • Use the blue hyperlink in the IPR result, and it will take you to the Condition check of transmission oil • Navigate to Xentry Bluebook > Help for control unit > Condition check of transmission oil If a different repair that what is recommended by IPR is performed, attaching photo documentation of the complaint vehicle oil pan and the IPR example to the claim is required. Reproducing the Concern: Proper evaluation of transmission concerns generally requires the condition to be reproducible. It is recommended to compare the vehicle to a similar model, if available, to help determine whether the shift behavior is characteristic of the drivetrain or uncharacteristic for the vehicle. If the concern cannot be duplicated: • A test drive with the customer may assist in understanding and reproducing the complaint. • The vehicle shift quality should be compared to a known-good vehicle with identical drivetrain and model year. • Check Shift Quality History (VGS Control Unit > Adaptations > Shift Quality History) Shift Quality History will show the last 5 noticeable harsh shifts and some of the parameters in which it occurred. You can use this to attempt recreation of the operating conditions and increase likelihood of reproducing the complaint. Complaint A: Shift Quality Note: Certain AMG variants may exhibit more firm and noticeable shift behavior as a normal characteristic. Refer to LI27.60‑P‑075147 for additional information. 1. Perform Valve flushing procedure 2. Perform 5 Torque Converter adaptions in a row - Allow the vehicle to warm up naturally, DO NOT power brake as it will increase the temperature in the torque converter. - After the 5th adaptation, collect a screen shot showing all 5 on one page 3. Perform a standstill adaption - collect a screen shot Recheck vehicle operation. If the concern has not improved, driving adaptations should be performed to target specific gear shifts.
LI27.00-P-080840
Service Bulletin/Repair Instructions
Complaint Mercedes-Benz USA is currently experiencing limited availability of transmission fluid specification ATF 236.17 due to a global supply constraint. 236.17 ATF 1L and 5L (PNs: A002989060312 and A002989060313) bottles are out of stock or in limited supply at Zep. This LI has been created with the following intention: - Provide dealers with additional workshop-focused guidance regarding the current ATF 236.17 supply constraint and the planned introduction of ATF 236.18. - Supplement existing communications and address common workshop questions related to maintenance, repairs, and fluid applicability. - Provide technical clarification and practical workshop guidance during the temporary supply constraint period. Dealers should continue to reference the latest News Channel Updates (NCUs) for the most current information regarding availability, ordering processes, supply status, and other related updates. Cause Damage to the Shell production facility has resulted in 236.17 oil supply being reduced to 50% of normal output until the end of 2026. Remedy Please first check Latest NCU updates for latest detailed information. Please continue placing orders through Paragon as normal. Supply is expected to remain reduced and allocation measures are currently in place. We ask for your patience through this restricted supply period. Most orders will be filled in the order in which they were received, as supply is replenished. Those dealers with zero inventory, and pending orders, will receive priority. We expect supply to be stabilized in September 2026. Approved Fluids: Only use transmission fluid from the approved list found on the Mercedes-Benz Operating Fluids website. Non-approved fluid will result in mechanical damage to the transmission and must be avoided. https://operatingfluids.mercedes-benz.com/sheet/236.17 Approved fluids can be claimed as follows if there is no Mercedes-Benz part number: Part # ATFSUB1L - TRANSMISSION FLUID 1 LITER ATFSUB5L - TRANSMISSION FLUID 5 LITER Dealerships with Zero Inventory AND Grounded Vehicles: If a vehicle is currently grounded for repair at your dealer due to no 236.17 inventory, we may be able to expedite your order. Please open a StarSupport ticket including the following information: (Parts Related Inquiry>National Accounts>Zep) • LI document number • Short explanation of repair needed for grounded vehicle • Current days down of RO Maintenance and Service Interval Guidance Published maintenance intervals remain unchanged. Vehicles should continue to be maintained in accordance with the applicable maintenance schedule. This LI does not revise or extend any published maintenance interval requirements. If all required parts and materials are not available prior to scheduling or beginning a transmission service, dealers should consider postponing routine preventative transmission maintenance until the necessary parts become available. For vehicles that have not yet reached the applicable maintenance interval and do not exhibit transmission-related concerns, there is no need to recommend preventative transmission services prior to the scheduled maintenance interval. When evaluating whether routine transmission maintenance can be deferred until parts become available, dealers should consider: • Overall vehicle condition • Vehicle usage and operating conditions • Presence of transmission-related symptoms or customer complaints • Customer expectations and vehicle operating requirements • Availability of required parts and materials Introduction of New Fluid Specification 236.18 Mercedes-Benz is currently preparing the introduction of ATF 236.18 as an additional approved transmission fluid solution for applicable NAG3 transmissions. At the time of publication of this LI, ATF 236.18 is not yet available for dealer ordering or workshop use in the U.S. market. See attachment for further details.
LI33.30-P-080490
Service Bulletin/Repair Instructions
Complaint Leakage/oil leakage at drive pinion sealing ring (input shaft) (Figures 1-2) Minor leakage/slight seepage at coupling flange nut at drive pinion (Figures 3-4) Cause Damage to sealing ring during production process or insufficient use of lubricating paste during assembly of collar nut on coupling flange Remedy If any of the above-mentioned customer complaints are present, or if oil leakage or seepage is found at the front axle differential during a workshop visit, the following steps must be performed: If oil leakage is found at drive pinion sealing ring (input shaft): • Remove coupling flange from differential, AR33.30-P-0550WT • Replace drive pinion sealing ring • New collar nut (for coupling flange), part number A 221 353 03 72, on contact surface and coat the 1st thread (from contact side to coupling flange) with lubricating paste (Figures 5-6) • Install coupling flange. If oil leakage or slight seepage is found at coupling flange nut to drive pinion: • Remove coupling flange from differential, AR33.30-P-0550WT • Clean threads on input shaft • new collar nut (for coupling flange), part number A 221 353 03 72, on contact surface and coat the 1st thread (from contact side to coupling flange) with lubricating paste (Figures 5-6) • Install coupling flange.
LI20.10-P-072886
Service Bulletin/Repair Instructions
Complaint Check Engine Light ON with DTC P012800 "The Coolant Temperature is Below the Specified Temperature" active and/or stored in the ME (N3/10). There are no drivability concerns related to this complaint. Cause Root cause varies Remedy Prior to performing any repairs for this complaint: With a cold engine, pressurize the high temp coolant circuit and while it's under pressure, release the cap on the low temp coolant circuit and check if the pressure drops right away or not. If the pressure drops, the lower coolant hoses are swapped. Correct this, fill, bleed and test drive the vehicle. If the complaint returns, then continue with the steps below. IMPORTANT: Use VMI to check for the following emission extended warranty –> Engine Thermostat (incl. software update) MY19-23, Various Models and Platforms (167, 190, 205, 213, 217, 222, 223, 232, 253, 290, 463) If the vehicle is covered under the above emission extended warranty, please perform steps outlined in the accompanying NCU prior to those outlined in this document. If vehicle is not covered under the above emission extended warranty or the complaint continues to occur, then proceed as follows: Check for available software updates to the ME (N3/10). If updated software is available, perform the update, clear the DTC and the perform each of the "WARM START" and "COLD START" test drives listed below twice. If the code does not re-appear then release the vehicle. If there is no new software available OR the DTC returns after the test drives then perform the following steps: • Drain the coolant through a fine mesh sieve and check for signs of debris. Additionally, inspect the coolant reservoir for debris. If any debris is found take pictures of the reservoir and the mesh filter and "flush" the system at least 2-3 times to clear as much of the debris as possible • Replace the thermostat and bleed the system as outlined in AR20.00-P-1142-04A, evacuate the system for 20-30 minutes instead of the 5 minutes specified in step 22 • NOTE: Please use all the tools specified in the AR document. The DTC will continue to populate if the circuit is not properly bled • NOTE: There are two valid thermostats to choose from in the parts section of this LI. Please verify which PN is applicable for the vehicle being worked on via XENTRY Parts Information • After bleeding the system clear the DTC and perform each of the "WARM START" and "COLD START" test drives listed below twice. If the DTC does not reappear after the tests, release the vehicle If the ME (N3/10) software is up to date, the thermostat has already been replaced, and the complaint persists open a TIPS case and attach the following documents: • Initial quick test • ME (N3/10) control unit log • The results of an R48 test from a “yes” response and from a “no” response • Pictures of the coolant reservoir and mesh sieve (mentioned above) WARM START · Begin with the engine coolant temperature at approximately 50 degrees C · Activate the AC system, if defrost is not in use open the windows · Drive the car normally until a coolant temperature of 75 degrees C is achieved · Depress the accelerator pedal 50% for ~5 seconds (partial acceleration) · Let off the accelerator pedal and let the car coast for ~10 seconds · Continue to drive the car normally COLD START · Drive for ~7 miles (normal driving) · Shut off the engine in a parking lot (or similar), wait 30 seconds, then restart and continue driving · Depress the accelerator pedal 50% for ~5 seconds (partial acceleration) · Let off the accelerator pedal and let the car coast for ~10 seconds · Continue to drive the car normally
LI27.60-P-080169
Service Bulletin/Repair Instructions
Complaint Complaints of a harsh 3to4 upshift Cause Lost torque adaptation values and negative fill times of clutch K27. Remedy Short-term measure: Note: All steps—including resetting the learned values and performing the stationary adaptation—must be completed to resolve the concern. 1. Perform IPR and follow the provided instructions. 2. Perform software update if available (IPR will automatically check for status of software availability) 3. Perform Special Function "Resetting of learned values 'Deceleration Mode'" (VGS > Special Procedures > Special procedure > Resetting learned values Deceleration mode) 4. Complete the standstill adaptation Long-term measure: A software resolution has been released for several model years with software levels 22A.3 (n3g222aa03ub) and 22A.4 (n3g222aa04ub). - Check VGS control unit log or eeprom .txt file for "Program Status" to determine your vehicle. Software is in the approval process for MY23 with 22A.3. Once the software is released, an update on availability will be added in IPR and in this LI document. As of 6/8, software released for the following model years: MY26 with 22A.4 A001 902 25 21 >> A001 902 96 21 MY24+MY25 with 22A.3 A000 902 26 99 >> A001 902 97 21 If the vehicle software level is not 22A.3 or 22A.4: A software resolution will not be created for these vehicles, please follow the short term solution to alleviate the concern.
LI40.10-P-059248
Service Bulletin/Repair Instructions
Complaint Crackling and cracking noise from the outer wheel on the front axle when cornering Cause The noise is generated by a micromovement on the contact surface between the rim and the brake disk (wheel bolt group) and may be intensified by potential soiling. The more lightweight rim (AMG forged rim) transmits the noise louder; in the case of cast rims, the noise is generally not perceptible. This is not a technical defect, but rather a complaint concerning comfort. Safe operation of the vehicle is ensured at all times. Remedy Important note: The operations described below do not represent a permanent remedy in every case. The noise may reoccur again after an indefinite period of time; sanding the rims with abrasive media multiple times is not permissible. Only cleaning using the Hazet tool 4960-160 (recommendation) can be performed without any concerns each time the wheel is changed or if the complaint reoccurs. Replacing the parts (rim, wheel bolts, wheel bearings, wheel hub, brake disk) is not expedient in the event of this complaint. ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Clean the components of the wheel bolt connection according to the WIS instructions Sand down the rim and brake disk bowl by performing the following steps: • Manually sand rim (old design only) in area of water drain bores (Figure 1; item A), approx. 1.5 cm left and right of water drain bore (Figure 2) Note: Use abrasive paper with grit size 80. The grooving in this area should no longer be visible (sand down approx. 0.1-0.2mm) • Also sand brake disk bowl using emery cloth or abrasive paper with a grain size of 120 • For vehicles equipped with the AMG ceramic brake system (B07), abrasive paper may not be used for cleaning on the brake disk side Note: Do not use any cleaning agent when cleaning on the rim side. Cleaning using abrasive paper with a grain size of 80 will suffice. Do not apply any grease, lubricant or paste after cleaning The brake disk bowl should be "bare metal" in the area of the imprints made by the hole (Figure 3)
LI35.30-P-058566
Service Bulletin/Repair Instructions
Single throttle lift-off clunking noise from the side shaft when moving off (audible at the outboard end). The noise is heard once in each instance when changing direction of travel. Note: Sound file in attachment Cause If the complaint is eliminated by experimentally loosening the outboard collar nut (by 1 turn), the problem is due to cracking of the microweld between the wheel bearing inner race and the joint housing of the side shaft. Note: The collar nut must always be replaced after being loosened. See also LI33.20-P-078406 Remedy Coat contact surface of side shaft with wheel bearing with Molykote paint. To do this, proceed as follows: 1. Remove side shafts 2. Clean contact surface A (see image file in attachment "Outer joint housing before") before coating with Molykote, using "spirit" (free of dust and grease) 3. Coat contact surface A (see image file in attachment "Outer joint housing after") with Molykote and leave to dry for "one hour" in removed condition 4. Reinstall side shafts Note: Before using the antifriction coating (Molykote), stir it or shake it thoroughly for (at least 1 minute).
LI33.20-P-078406
Service Bulletin/Repair Instructions
Complaint Creaking noise, in irregular sequence when driving slowly in combination with slight steering movements and/or Creaking/crackling noises from the area of the wheel bearing on the front axle when cornering/ maneuvering. Sound file attached for comparison. MUST match noise for proper diagnosis. NOTE: Steering functionality is not affected. Cause Contact area between wheel bearing and steering knuckle. See also: LI35.30-P-058566 (Throttle Lift-Off Noise - Rear) LI33.30-P-056665 (Throttle Lift-Off Noise - Front) LI40.10-P-059248 (Wheel cracking noise when cornering) Remedy 1. Perform Operation A and evaluate by testing vehicle. 2. If noise is still present after re-testing: • If 192/232 chassis, verify FIN is in the listed range below in "Operation B" and perform. • If not 192/232 chassis or vehicle is a 192/232 not in the listed FIN range, additional verifications of where the noise is coming from are needed. Use multiple channel NVH method to narrow down location. Verify the LI's listed above were completed or if there are other similar noises associated with the chassis (Example: 192/232 also has under panel noises and an associated LI). Operation A: 1. Clean contact surfaces of wheel bearing and steering knuckle with brake cleaner as seen in the attached pictures. NOTE: The front area of the wheel bearing and the seals must not come into contact with the cleaner, otherwise, the sealing rings will be damaged. 2. Clean threads of wheel bearing mounting. 3. Thinly coat contact surfaces of wheel bearing, steering knuckle, and axle mating face with Molykote (annular joint grease). See the attached steering knuckle and wheel hub pictures for reference. NOTE: Axle mating face greasing is also covered in LI35.30-P-058566 and LI33.30-P-056665. Operation B (Only applies to 192 and 232 in listed FIN range): Only affects vehicles up to FIN end number: • Model series 192: xxx xxx xx 002 876 • Model series 232: xxx xxx xx 022 312 1. Replace steering knuckle. 2. Wheel bearings do not need to be replaced.
PSL-NCU Return Parts 7/3
Other
Dear Mercedes-Benz USA Dealers, The part numbers listed in the chart below should no longer be installed, and any existing stock must be returned to your facing PDC. The deadline for all dealer returns is no later than Thursday, July 23rd, 2026. After July 23rd, returns of these parts will no longer be accepted. These parts should be returned via ZSR Special Return, using item category SCM Authorized Part Return. Please include a copy of this NCU as your authorization to return these parts. This procedure will not affect your return allowance. All returned parts will be replaced in accordance with the chart provided below.
LI00.20-P-077615
Service Bulletin/Repair Instructions
Complaint 1. "Perform vehicle handover" in the workshop menu to start the maintenance computer for service A/B cannot be carried out. 2. Service confirmation is not possible because "Perform vehicle handover" is displayed. This cannot be carried out. 3. The service display in the instrument cluster permanently displays 365 days (remaining time) and does not change. Cause Routine change in the software in N133/1 (instrument cluster) or A26/17 (MBUX multimedia system and instrument cluster (head unit)). Vehicle handover was not performed. Remedy For model series 290 AMG up to and including AEJ 22 and model series 167 up to and including AEJ 21/2, the following applies: Manually commission already-installed instrument cluster control unit N133/1 and then perform special procedure to re-initialize ASSYST data in N127 powertrain control unit. The following applies to model series 167 from AEJ 22/1 onward, 192 AMG, 206, 214, 223, 232 AMG, 236, 254, 290 AMG from AEJ 23 onward, 294, 295, 296, 297 and 465: Reinitialize ASSYST Plus under Adaptations – Teach-in processes – ASSYST PLUS in control unit N133/1 (instrument cluster) or A26/17 (MBUX multimedia system and instrument cluster (head unit)), and then perform the special procedure for reinitializing the ASSYST data in powertrain control unit N127.
LI54.30-P-080649
Service Bulletin/Repair Instructions
Complaint General information on the operation of the PRE-SAFE® Impulse system: The PRE-SAFE® Side Impulse system is a preventive, i.e. pre-collision occupant protection system. The task of the system is to provide additional protection to vehicle occupants when there is a risk of a side impact. It is not a restraint system component in the conventional sense and does not contain an detonator. A potential side-impact situation is detected by radar sensors. If the system detects an existing likelihood of a side impact, a reversible air cushion in the outer seat side bolster is briefly inflated by opening a valve. The resulting pulse preemptively increases the distance between the door and the occupant in order to move the occupant out of the danger zone. If the system has been activated, the following message appears on the instrument cluster: PRE-SAFE® Side Impulse inoperative. See Operator's Manual. Note: After system activation, diagnostic entry B1B3713 or B1B3813 is marked as active and stored in the ORC223 (N2/5) control unit. Cause After activation of the “PRE-SAFE® Side Impulse” system, the function is no longer available. Remedy Please check the tight seating and possible damage of the radar sensors B29/11 or B29/12. Then replace the gas generator on the affected side (R12/65 or R12/66). After replacing the gas generator (R12/65 or R12/66), please perform commissioning and SCN coding of the radar sensors B29/11 or B29/12 to ensure they are up to date. Note: In principle, it is not necessary to replace the air cushion in the "PRE-SAFE® Side Impulse" system, as it is designed for multiple activations (up to 10). Exception: After deployment of the sidebag (e.g., following a crash), exchange (air cushion with gas generator) of the "PRE-SAFE ® Impulse Side" is required in all cases.
ANN - S/223_EQS/297
Other
For awareness, after SW update of control unit, IC223, on models 223 and 297, seat belt lamp and chime remains on. Thank you for your patience while we find a solution.
PSL-NCU Return Parts 6/19
Other
Dear Mercedes-Benz USA Dealers, The part numbers listed in the chart below should no longer be installed, and any existing stock must be returned to your facing PDC. The deadline for all dealer returns is no later than Thursday, July 9, 2026. After July 9th, returns of these parts will no longer be accepted. These parts should be returned via ZSR Special Return, using item category SCM Authorized Part Return. Please include a copy of this NCU as your authorization to return these parts. This procedure will not affect your return allowance. All returned parts will be replaced in accordance with the chart provided below.
LI00.20-P-078424
Service Bulletin/Repair Instructions
Complaint The remaining time shown on the instrument cluster in the workshop menu (days to next due service) is implausible (>365 days) for the following conditions: • for the date of the vehicle handover • or the last conducted and confirmed Service A/B Cause Case 1: Observe the following on vehicles with a disconnected on-board electrical system battery (12V/48V): • The period in which the on-board electrical system battery is disconnected cannot be counted by the maintenance computer. • As soon as the on-board electrical system battery is connected again, the maintenance computer automatically starts counting without making a correction to the remaining time (days until the next service). Case 2: If a disconnected on-board electrical system battery (12V/48V) can be ruled out as the cause, it is possible that: The daily turnover counter inside the electronic ignition lock (EIS) has experienced memory loss. This anomaly was detected in the EIS software from modification year 2022 onward. To do this, please check the plausibility of the daily turnover counter as follows: If "TUSZ Assyst Plus" < the actual days since "Handover Date/DAY/Month/Year," then proceed to remedy for case 2. Information: A variation of 2-3 days is still considered plausible. If "TUSZ Assyst Plus" is plausible, or if a remaining time of 365 days is permanently displayed, check whether the vehicle has been handed over. These types of cases have different causes. (The respective values are included in the maintenance data in the control unit log of the instrument cluster). Remedy For case 1: When the on-board electrical system battery is disconnected, this period must always be taken into account for these vehicles, and the following condition must be met for a correct calculation to be made: • (A): The number of days from the "date of vehicle handover or last service A/B" to the "date on which the vehicle arrived at the workshop." • (B): Remaining time (days until the next service, as shown in the instrument cluster). • (C): Days on which the on-board electrical system battery was disconnected. The formula requires the following condition to be complied with. 365 - (A) [days] = (B) - (C) [days] For case 2: If the on-board electrical system battery (12 V/48 V) was not disconnected and the remaining time shown in the customer or workshop menu on the instrument cluster (days until the next service) is implausible in terms of the date of the vehicle handover or the last performed and confirmed service A/B, or the condition in the formula was not met, the service can still be performed and confirmed. For vehicles arriving more than 90 days after the service due date, the DSB service history can only be corrected by re-entering "Vehicle regularly serviced." A software fix for the EIS (electronic ignition lock) is currently in planning. The objective is to have a remedy available for 2026. Until the remedy is available, it is advisable to inform the customer that the next service is due again after 365 days at the latest.
LI07.61-P-080241
Service Bulletin/Repair Instructions
Complaint CEL ON with DTC P061197 "The control unit 'fuel injector' has a malfunction (output stage fault of control unit 'combustion engine'). The system function is restricted." active and/or stored in the ME (N3/10). There are no drivability concerns related to the complaint. Cause ME (N3/10) software Remedy Updated ME (N3/10) software is available for affected models. Below are the remedy software object numbers for each affected variant: MY24 - A1769037801 MY25 - A1769037901 MY26 - A1769038001 Once the ME software is updated: clear all DTCs, reset self adaptation of mixture, and perform an AMG adaptation drive.
PSL-NCU Return Parts 6/05
Other
Dear Mercedes-Benz USA Dealers, The part numbers listed in the chart below should no longer be installed, and any existing stock must be returned to your facing PDC. The deadline for all dealer returns is no later than Thursday, June 25, 2026. After June 25th, returns of these parts will no longer be accepted. These parts should be returned via ZSR Special Return, using item category SCM Authorized Part Return. Please include a copy of this NCU as your authorization to return these parts. This procedure will not affect your return allowance. All returned parts will be replaced in accordance with the chart provided below.
LI88.85-P-080644
Service Bulletin/Repair Instructions
Complaint The Maybach emblem at the C‑pillar is detached from the vehicle Cause The adhesive bond has failed Remedy The adhesive has been optimized. Perform replacement of the Maybach emblem on both sides of the vehicle. Note: The old part numbers include the updated adhesive and may be used if the newer parts are not available.
LI46.15-P-070510
Service Bulletin/Repair Instructions
Complaint Noises from the area of the steering column. - Creaking - Squeaking - Chattering - Humming - Grinding Cause At present, there are no known noise problems with the steering column. Remedy Check surrounding area of the steering column for possible noises. • Instrument panel support • Steering column switch module NOTE: Occasionally to verify complaint, the steering column/vehicle needs to be in direct sunlight or hot conditions for a few hours. If noise only occurs when adjusting the steering column via electric actuation, please perform: 1. Disassemble bellows of steering column tube module. 2. Move steering column entirely out and entirely down. 3. Grease steering column on all pivot points including, but not limited to, green-marked positions with a suitable brush (find pictures in attachment). 4. Move column up 1/4 of the way and grease again. 5. Continue until upper limit stop is reached. 6. Then move steering column adjustment in all directions from limit stop to limit stop several times to work in the grease. 7. If noise does not resolve, wipe excess grease off and perform greasing and movement to limit stops in all directions again. For all other noises or if the above does not resolve, create a TIPS case Body, Chassis, and Entertainment inbox. Attach a detailed description of the noise complaint, images, and a recording of the noise. Include detailed items of the following: • Position of height and longitudinal adjustment when the noise occurs • If possible, locate affected component part on steering column • State any change in the noise when steering column component parts are touched (e.g. spring, etc.)
PSL-NCU Return Parts 5/22
Other
Dear Mercedes-Benz USA Dealers, The part numbers listed in the chart below should no longer be installed, and any existing stock must be returned to your facing PDC. The deadline for all dealer returns is no later than Thursday, June 11, 2026. After June 11th, returns of these parts will no longer be accepted. These parts should be returned via ZSR Special Return, using item category SCM Authorized Part Return. Please include a copy of this NCU as your authorization to return these parts. This procedure will not affect your return allowance. All returned parts will be replaced in accordance with the chart provided below.
LI54.10-P-080602
Service Bulletin/Repair Instructions
Complaint 48V battery (A66) part numbers A 000 982 78 24, A 000 982 57 30, A 000 982 88 31, A 000 982 50 32, A 000 982 87 32) may trigger a fault message ("48 V Service Required" with fault codes P0ADA91, P0ADE91, P0AA100, P0ADD00 or P0AA000) in the instrument cluster. This fault message may prevent the 48 V battery contactors from opening automatically if the 12 V power supply is interrupted. In this case, the 48 V on-board electrical system, including connected components, remain energized. Cause The contactors of the 48 V battery do not open, resulting in residual voltage (> 3V) even when the 12 V battery is disconnected. Remedy When working on the 48 V on-board electrical system or connected components, ensure the component being repaired is de-energized in the 48 V system after disconnecting the 12 V ground line. Use a DVOM and ensure that there is less than 3V across the 48V terminals. • If the voltage is less than 3V, the repair can be continued in accordance with the WIS documentation. • If the voltage is greater than 3V, disconnect the ground line from the 48 V on-board electrical system battery and secure from contacting any ground points of the vehicle before continuing the repair. Once the work has been completed, follow the procedure for clearing the 48 V battery fault message as specified.
LI91.16-P-073576
Service Bulletin/Repair Instructions
Complaint • Driver's seat and/or front passenger seat cannot be adjusted. • Not possible to adjust front seats to memory preset. • Head restraints of front seats cannot be adjusted. • Cannot move to chauffeur mode/reclining seat position. Fault identification: → Create log of seat control unit (both conditions must be met) 1. Fault B1F7E54 "Head restraint inclination adjustment not normalized. No calibration." stored in fault memory. 2. Value "0C" present in seat control unit log service 0X220239 (see attachment "seat control unit log"). If fault B1FBB15 "Malfunction in 'Head restraint inclination' switch. There is a short circuit to positive or an open circuit." is also stored in the fault memory, the cause might also be due to the wiring or terminal contacts. Cause Faulty head restraints Remedy Replace the affected head restraint
LI82.30-P-059239
Service Bulletin/Repair Instructions
Complaint There are several types of complaint about noises or poor windshield wiper wiping performance: A: Wiper blades squeaking, chattering, shuddering B: The windshield is not wiped completely (streaking) C: During the downward movement water is pulled back onto the windshield from the A-pillar (Figure 1) D: After windshield cleaning, water keeps spraying onto the windshield for several wipe cycles (Figure 2) A1: The windshield and wiper blades are contaminated with residues from car washing facilities, identifiable by the water beading. The resulting differences in the friction values between the wiper blades and the windshield can excite the wiper blades to vibrate. Note: It is mostly wax residue from the washer system, but also water-repellent nano-particle coating for paint and/or silicone-based washer fluid, that could cause this problem. A partially dry windshield also has different friction values, which can likewise result in squeaking of the wiper blades A2: The wiper blades are worn by mechanical damage (wiper lip damaged by ice or insect debris, or deformed by long periods of disuse). A3: Incorrect angle of incidence of the wiper arms to the windshield. Because of this, the rubber lip of the wiper blade may not flip over at the reversal point. Cause B: B1: Wax/ dirt residues on the windshield B2: Wiper blades deformed or worn B3: Downforce of wiper arm not OK (Figure 3) Cause C: Water is pulled back onto the windshield by the differential pressure created as the wiper arm moves downwards. Cause D: Washer water collects in the fastening of the wiper blade and is blown onto the windshield by the airstream over several wipe cycles. Note and supporting information: Wiper blades are wear parts which, even when "not used" for long periods (kept in park position), may become permanently deformed and damaged. Further stresses on the rubber wiper blade arise due to various environmental influences which progressively change the effectiveness of the rubber wiper blade and accelerate the aging process. Due to the natural aging process and wear, the wiper blades should be replaced twice a year, preferably in Spring and Fall (see operator's manual). Remedy Remedy A: A1: Cleaning entire windshield with A 000 986 40 71. A2: Checking water's flow behavior after windshield has been cleaned (see Video 1). If, after cleaning, there are still areas with water beading, then the cleaning process must be carried out again until a rejection reaction is no longer present. • Note: On the vehicle in the video (Video 1), water still beads on the bottom left of the windshield. The windshield is still not properly clean, even though it appears to be clean. The windshield is only properly clean when there are no more areas on the windshield where water beads. A3: Replace wiper blades with genuine wiper blades. Important: Only exchange wiper blades if windshield no longer has water-repellent areas Note: Replacement of wiper blades is not covered under warranty and can be replaced at the expense of the customer. Remedy B: B1: Clean windshield with intensive cleaner A 000 986 40 71. Important: Do not clean the wiper blades otherwise the graphite coating will be damaged. B2: Replace wiper blades with genuine wiper blades • Note: Replacement of wiper blades is not covered under warranty and can be replaced at the expense of the customer. B3: Check the wiper arm for excessive resistance in the bearing. Restore mobility or replace wiper arm if necessary. Remedy C: Problem inherent in design for which there is no technical remedy. Exception: X204 up to 02/2014. In these vehicles, it is possible to install the design configuration of vehicles as of 02/2014. This includes wiper arms (styled arms) with improved behavior in this respect. It is also necessary to replace the wiper blades because the styled arms feature a Top Lock connection (previously Side Lock).
LI91.29-P-080554
Service Bulletin/Repair Instructions
Complaint One or more seat functions are restricted or inoperative. This may include: • Seat memory • Automatic seat adjustment • Easy Entry/Exit • Head restraint presetting • Collision avoidance with bench seat at rear • Actuation by other vehicle systems Seat normalization is missing, and fault code B228678 – “The control unit calibration has been lost or was not performed. Adaptation or adjustment is not correct.” is stored in the seat control unit. Additional fault codes may also be present. Cause The condition is currently under investigation. Remedy Process any additional faults first. • If a clear cause is found (for example, a failed component, wiring issue, or connector concern), repair that issue as required. If no root cause can be determined: • Do NOT perform Initial Start-up, Software Update, or Normalization of the Control Unit • Create a control unit log for the affected seat control unit. • Open a TIPS case to the Body/Chassis/Entertainment inboxand attach the control unit log for further analysis.
PSL-NCU Return Parts 5/15
Other
The part numbers listed in the chart below should no longer be installed, and any existing stock must be returned to your facing PDC. The deadline for all dealer returns is no later than Thursday, June 4, 2026. After June 4th, returns of these parts will no longer be accepted. These parts should be returned via ZSR Special Return, using item category SCM Authorized Part Return. Please include a copy of this NCU as your authorization to return these parts. This procedure will not affect your return allowance. All returned parts will be replaced in accordance with the chart provided below.
LI00.01-P-078887
Service Bulletin/Repair Instructions
Complaint The intent of this document is to provide workshops with helpful technical reference language. • Commonly used acronyms in LI's and TIPS cases. • Control unit names, numbers, and how to identify. • Network/wiring architecture groups to baumuster quick reference. • Platform to baumuster quick reference. Cause Information only Remedy Acronyms: • AV = Actual Values • CPR = Car Package Release (For MB.OS) • CU = Control Unit • CUL = Control Unit Log • DTC = Diagnostic Trouble Code • E-Stand = Fresh-up head unit boot software (found in head unit control unit log) • FUP = Fresh-up • FW = Firmware • HSVL = High Speed Video Line • HU = Head Unit • HW = Hardware • IPD = Injector Performance Data • ISU = Initial Start Up • LVDS = Low Voltage Differential Signal • NAG"x" = New Automatic Gearbox ("x" is the generation number, example: NAG3) • NSFT = Not Safe For Transport • MOPF = Model Facelift (Ex: 167 MOPF) • PiH = Plug-in Hybrid • SA Code = Sonderausstattungscode (Option Code) • SCN = Software Calibration Number • SW = Software • TCU = Telecommunication Control Unit (Hermes/Ramses/Etc...) • QT = Quicktest • XD = XENTRY Diagnosis Control Unit Identification: Refer to the attachment "Control Unit Nomenclature" for location of each. • Control Unit Name • Control Unit Number • Control Unit Short name • Control Unit Diogenes ("dy-oj-uh-neez") name - Control unit variant/family. Network/Wiring Architecture to Baumuster Quick Reference: Star 1 • 117, 156, 246 (MFA) • 166, 176, 221, 242, 246, 292 • 906 Star 2 • 205, 213, 238, 253, 257, 290 (MRA) • 117, 156, 246 (MFA) • 118, 177, 243, 247 (MFA2) • 167, 222, 292, 463, 465 • 907 Star 3 • 294, 295, 296, 297 (EVA2) • 206, 214, 223, 236, 254 (MRA2) • 192 and 232 (MSA) Star 3.5 • 174 • 178 Platform to Baumuster Quick Reference: MRA = "Mercedes-Benz Rearwheel Architecture": • 205 • 213 • 222 • 238 • 253 • 257 • 290 MRA2 = "Mercedes-Benz Rearwheel Architecture - Generation 2": • 206 • 214 • 223 • 236 • 254 MFA = "Mercedes-Benz Frontwheel Architecture" • 117 • 156 • 246 MFA2 = "Mercedes-Benz Frontwheel Architecture - Generation 2" • 118 • 177 • 243 • 247 EVA1.5 = "Electric Vehicle Architecture" • 243 EVA2 = "Electric Vehicle Architecture - Generation 2" • 294 • 295 • 296 • 297 MSA = "Mercedes-Benz Sport Architecture" • 192 • 232 MMA = "Mercedes-Benz Modular Architecture" • 174 • 178
LI72.20-P-080324
Service Bulletin/Repair Instructions
Complaint Trunk lid lock may not unlock when the trunk lid handle (S88/8) is operated The trunk lid can still be opened using the following methods: • HFA (Hands-Free Access) • Unlocking and opening the trunk from inside with the emergency release • Trunk lid remote operating switch at the drivers door • Press and hold the "Trunk lid" button on the SmartKey Cause Under analysis Remedy Check switching signal of trunk lid handle (S88/8) during operation and document results by providing print out of actual values. Submit a TIPS case with fault description and observations. • send to the Body/Chassis/Entertainment inbox.
LI82.10-P-078301
Service Bulletin/Repair Instructions
Complaint Headlamp, front fog lamp leaky or fogged. Cause Fogging of the headlamps is a natural phenomenon, which can occur under certain climatic conditions. It does not lead to any technical impairment of the headlamp. If a pressure compensation diaphragm is fitted in the housing cover, then the lamp unit is a "closed system". Remedy Headlamp: Remedy 1 Clearing fogged/condensed LED headlamps: 1. Drive vehicle into workshop (temperature higher than +18 °C/+64.4 °F) and connect the exhaust extraction. Note: Do not perform an engine wash before the defogging test. 2. Switch off the engine and connect battery support via a charger. 3. Open the hood. 4. Switch on the lights. 5. Leave the vehicle in this state for 60 minutes. 6. Check for formation of condensation, a significant reduction in the formation of condensation must be clearly recognizable (thawing progress). Clearing of fogged/condensed LED headlamps and LED rear lamps on electric vehicles: 1. Drive the vehicle into the workshop (temperature higher than +18 °C/+64.4°F). 2. Connect battery backup via a charger. 3. Open the front-end flap and ensure sufficient ventilation. 4. Switch on the lights. 5. Leave the vehicle in this state for 60 minutes. 6. Check for formation of condensation, a significant reduction in the formation of condensation must be clearly recognizable (thawing progress). Clearing fogged/condensed halogen/xenon headlamps: 1. Drive the vehicle into the workshop (temperature higher than +18 °C/+64.4°F). Note: Do not perform an engine wash before the defogging test. 2. Switch off the engine. 3. Open the hood. 4. Switch off the lights. 5. Leave the vehicle in this state for 60 minutes. 6. Check for formation of condensation, a significant reduction in the formation of condensation must be clearly recognizable (thawing progress). Note: If there is no visible reduction in condensation, check the headlamp for malfunctions. (see Remedy 2) It is not physically possible to defog the headlamps completely. Fogging does not impair the operation or the service life of the headlamp. Note: Only implement Remedy 1 for model series 463 (from model year 2018) and model series 465. Remedy 2 A defective headlamp can be identified as follows: 1. Check the headlamp for external damage and that the cover caps and the diaphragm are correctly seated. 2. Check the electrical connectors of the plugs and pins. 3. Check for leak tightness according to LI82.10-P-078307. The test can only be conducted on headlamps. 4. If the headlamp or the rear lamp has any external damage, replace the component part in accordance with the WIS instructions. Note: External damage to the headlamp/rear lamp or faulty seating of the cover caps does not present a warranty or goodwill case. Note: With headlamps, it is possible to install desiccant packs if the problem occurs repeatedly. • Open ventilation system LI82.10-P-078302 • Closed ventilation system LI82.10-P-078304
LI91.60-P-076303
Service Bulletin/Repair Instructions
Complaint SRS indicator light illuminated in the instrument cluster. Electrical fault in the rear airbag/window airbag that may cause a connection between the airbag pins or to the vehicle mass Cause Contact problems that create a short circuit between the pins or to the vehicle ground Remedy Connect and disconnect the affected airbag five times Then the squib must be carefully blown out with dry compressed air. Caution: There must be no mechanical contact! If fault is not rectified: Please measure the internal resistance as described in SI91.00-P-0005A. If the resistor of the airbag is OK, please replace the airbag plug. If the resistance of the airbag is not OK, please replace the airbag. Important: The electrical fault does not affect the functionality of the airbag in the event of an accident. The airbag is functioning as intended.
LI46.80-P-079280
Service Bulletin/Repair Instructions
Complaint Rattling/knocking noise from the rear axle steering is audible when driving on rough terrain or cobblestones. Excessive radial play (green arrows) between the screw-on stud (1) and the plain bearing (2). Cause Diverse functional play in the rear axle steering. Remedy 1. Detach underfloor paneling under rear axle steering. 2. Remove heat shield. 3. Remove large clamps from left bellows. 4. Open small clamps on left using a suitable tool and slide to the side. 5. Slide bellows to the side. 6. A second person sits in the vehicle and, with the drive activated and the automatic transmission in the N position, turns the steering to left lock. Caution! Risk of trapping when steering at the same time! Do not move steering wheel during operation steps 7 and 8! 7. Remove grease from screw-on stud using a clean, lint-free rag. => Up to the area where the stud enters the bearing! Then completely degrease the threaded stud using a lint-free cloth soaked in a suitable assembly cleaner (e.g., A 000 986 56 01); if necessary, clean hard-to-reach areas with the assembly cleaner. => Up to the area where the stud enters the bearing! Important: The surface must be thoroughly cleaned and free of grease! 8. Then apply Hylomar (A 001 989 25 20 09) around the degreased screw-on stud using a new brush. => Up to the area where the stud enters the bearing! 9. Move steering wheel from end stop to end stop 1-2 times. Then, turn the steering to the left lock again. Warning! Risk of trapping when steering at the same time! 10. Apply Hylomar a second time. 11. Move steering wheel from end stop to end stop 1-2 times. Then, turn the steering to the right lock. Warning! Risk of trapping when steering at the same time! 12. Bellows installation: Coat contact surfaces of bellows and rack-and-pinion steering lightly with Renolit (A094 989 38 00). When doing so, ensure that the grease is underneath the edges of the bellows. Replace large clamps (A 001 995 15 35). The small clamp can be reused. 13. Repeat operation steps 3 to 5 on the other (right) side. 14. Then repeat operation steps 7 to 12 for the screw-on stud on the other side. 15. Attach heat shield. 16. Attach underfloor paneling. 17. When relocating the vehicle on the premises, please use Snow Chain Mode through the head unit to limit speed so Hylomar application stays in place. 18. Leave the Hylomar to dry for approx. 90 minutes. Note: Deactivate Snow Chain Mode after stopping the vehicle! 19. Then perform a test drive. If the remedies are not effective => please create a TIPS case to the Body/Chassis/Entertainment with the following information: • Complete history of the rear axle steering with mileage and repair date along with what was completed (application of Hylomar, replacement of the rear axle steering). • Clear video or audio file of the complaint as perceived by the customer (without amplification via Chassis Ear or similar devices and not on the shock absorber test stand).
LI46.10-P-079374
Service Bulletin/Repair Instructions
Complaint Customer concern for ESP/Brake or Steering yellow instrument cluster message AND C220564 in the N80 Steering Column Control Module (Valeo Parts only). To check which supplier steering column module is present in the vehicle, see attachment "Supplier Identification". Cause Triggered due to communication related software timing. Remedy New software A2239026336. Update N80 (Steering Column Module) to at least target software A2239026336, clear codes, and ignition cycle the vehicle. If DTC is still present, re-flash N80 and clear DTC's. Is DTC still present? No --> Bus sleep the vehicle. After bus sleep check for DTC again. If DTC is not present, release vehicle. Yes --> Open a TIPS case to the Body/Chassis/Entertainment inbox.
LI80.20-P-078308
Service Bulletin/Repair Instructions
Complaint Depending on the identified problem (items 1-4), please implement the corresponding Remedy below (items 1-4): 1. KeylessGo sensor surfaces do not respond. Door handles can extend/retract if the key is used for locking/unlocking. No particular fault code. 2. Surface-flush door handle fails to retract and/or extend. One or more of the following fault codes are current and stored: B185D96; B185E96; B186196; B186296 The following values are present in the control unit log (A17/x): Motor_bridge_connection_fatal_error = True (for example, see attachment) OR Motor_bridge_wrong_direction_fatal_error = True (for example, see attachment) 3. Surface-flush door handle fails to retract and/or extend. One or more of the following fault codes are current and stored: B185D96; B185E96; B186196; B186296 The following values are present in the control unit log (A17/x): Motor_init_error_for_sensors = True (for example, see attachment) 4. Surface-flush door handle fails to retract and/or extend. The fault code B185911 is stored in the DCU (N69/X). Cause 1. Software bug. 2. Software robustness. 3. Software robustness. 4. The motor resistance is outside the tolerance range. Remedy Depending on the identified Complaint above (items 1-4), please implement the corresponding remedial actions (items 1-4): 1. Perform a reset of the corresponding 'KEYLESS GO' door handle control unit (A17/x) via XENTRY (for example see attachment) add-on is available (add-on 32204 for XENTRY version 06/25) Please use one of the following damage codes: 8213H73; 8219773; 8213K73; 8219873 2. Please process the guided fault check via XENTRY (Add-on 32485 for XENTRY version 06/25; Add-on 32486 for XENTRY version 09/25). In the event of a proposed SCN coding, it must be carried out and the faults must then be cleared. Please use one of the following SSLs: 8213H73; 8219773; 8213K73; 8219873 3. Please process the guided fault check via XENTRY (Add-on 32485 for XENTRY version 06/25; Add-on 32486 for XENTRY version 09/25). In the event of a proposed renewal of the bearing bracket, the corresponding bearing bracket must be replaced. Please use one of the following SSLs: 80A0D73; 80N0D73; 80N0E73; 80A0E73 4. The motor resistance is too low. Bearing bracket must be replaced. Please use one of the following SSLs: 80A0D73; 80N0D73; 80N0E73; 80A0E73 Please note that other published GI documents may also be valid for assessing the problem. For example: "LI72.10-P-074316 Flush-Mounted Door Handle Jams When It Is Pulled Out". Please also refer to SI72.00-P-0014A in WIS. If after the remedy points above are performed, the problem is still present, please submit a TIPS case to the PTS-Body/Chassis/Entertainment inbox. → In this case, store the damaged parts for further analyses.
LI82.85-P-077914
Service Bulletin/Repair Instructions
Complaint Mercedes me connect services inoperative (me-Call, Remote Status, etc.). Mercedes me services - activation not possible Notes: - The event code "B129C00 - Malfunction in control unit for telematics services" is active and stored - The head unit shows no internet connection Cause Under analysis. Remedy Please create a TIPS case, attach a RAMSES control unit log to the case.
LI82.85-P-080359
Service Bulletin/Repair Instructions
Complaint Mercedes me connect services inoperative (me-Call, Remote Status, etc.). Mercedes me services - activation not possible Notes: - The event code "B16AC00 - The configuration of the SIM card is erroneous" is active and stored - The head unit shows no internet connection Cause The RAMSES module may be faulty. This fault profile can be recognized as follows: With XENTRY Diagnosis, enter the "ACTUAL values" menu of the RAMSES control unit and read out the values with position 175 and 727. ACTUAL values in the event of a fault: Type of mobile service (position 175): No reception Operating mode (position 727): Ready mode Remedy If B16AC00 is permanently active and saved and position 175 is no reception and position 727 is ready mode, it is highly likely that the communication module is faulty. In this case, an initial start up must be carried out. If the problem persists even after an initial start up, please create a TIPS case.
LI82.85-P-078722
Service Bulletin/Repair Instructions
Complaint The vehicle's position on the map is displayed far away from its actual position, e.g. the vehicle is displayed as being in the middle of the ocean. Note: No relevant DTC is displayed during the quick test. Cause The GNSS antenna is not correctly inserted at the GNSS connection (see picture in the attachment) in the head unit (A26/17). Remedy Insert the plug into the GNSS connection and ensure that the plug has engaged correctly.
LI82.00-P-080029
Service Bulletin/Repair Instructions
Complaint The seat may no longer be adjustable using the electric seat adjustment switch on the door module. No related error is stored in the quick test. Cause Under certain conditions, the electric seat adjustment switch may remain in sleep mode. It is then not possible to adjust the seat using this switch. This is a software error. Remedy To restore functionality, perform the following steps: 1. Remove the door trim from the affected door. 2. Unplug and reconnect the plug of the electric seat adjustment switch (No. 2 in the picture in work instruction AR91.29-P-2522WT) to perform a reset of the switch. Note: The switch does not need to be removed for this. 3. To prevent this problem from recurring, the current software version A2239029930 should be installed on the switch module “Seat Adjustment Switch Group …”. Example: S22 - Select S22 – “Seat Adjustment Switch Group, front left” (SSE-VL) → Adaptations → Control unit update → Update control unit software. If the vehicle already has SW version A2239029930, there is another cause. Please open a TIPS case to the Body/Chassis/Entertainment inbox if the issue persists with the new software installed.
LI54.10-P-073164
Service Bulletin/Repair Instructions
Complaint Yellow information message in driver display (instrument cluster): "Switch on motor to charge the 12V battery" Cause The state of charge (SOC) of the 12V battery has dropped to 45% or less. Remedy This warning message appears as soon as the state of charge (SOC) of the 12V primary battery drops below 45%. This message is displayed to safeguard the vehicle's starting ability. At the same time as the display appears in the instrument cluster, customers with a linked Mercedes me connect account also receive a push notification via the app/by email (if this function is activated). The battery must be charged to a state of charge (SOC) of at least 50%. To do this, an external charger can be connected (please comply with AR54.10-P-1133S) or the vehicle can be driven (by the customer) for 30 to 60 minutes. Please make customers aware of how the vehicle behaves: • If the vehicle is used for short journeys, the battery state of charge may slowly drop to less than 45% – a negative charge balance • A negative charge balance will also occur if the vehicle is used while stationary without running the engine, e.g. if the head unit is used, the ignition is switched on, or other comfort & convenience power consumers, e.g. seat heating/seat ventilation, are active. • An unlocked vehicle may increase consumption, because certain vehicle functions are actively kept ready for the customer. In combination with Keyless-Go or flush-mounted door handles, the vehicle may be woken up if the vehicle key is detected in the vicinity of the vehicle. The cause of the discharge can be identified with the aid of the onboard electrical system data in the EZS using XENTRY Diagnosis. See attached examples for identifying typical customer situations (e.g. operation with ignition on, operation of head unit while stationary or vehicle unlocked while parked). Vehicles with code B01+801: When charging while stationary, the 48V battery must have a state of charge (SOC) of 70% before the 12V primary battery, or the secondary battery in the case of code 503, can be charged. To ensure optimum battery care, please also comply with the existing Service Information documents regarding the handling of stock vehicles (SI54.10-P-0024A) and on remaining in transport mode (SI54.00-P-0004A) until immediately before handover to end customers. Special note: Do not replace any parts, if the message has occurred due to battery discharge as a result of the driving profile or the ignition being switched on (see attached examples); in such cases separate warranty and goodwill invoicing is not possible, as this is a normal on-board electrical system protection function. Likewise battery care and recharging do not qualify as a W&G case. Please advise customers accordingly regarding the above-mentioned issues relating to vehicle use.
LI82.90-P-080159
Service Bulletin/Repair Instructions
Complaint Stored DTC C220564 - "There is an internal fault in the steering angle sensor. There is an implausible signal." In the quick test, there are also no other DTC's in other control units that point to or reference N80 Steering Column Control Module ("SCCM"). There is no effect on any other components or vehicle functions and it does not cause an instrument cluster light. Cause The DTC only ever occurs during initialization (initialization occurs after bus sleep). The SCCM then resets itself. Remedy 1. If the error is stored and no other control unit points to the N80 SCCM – ignore and erase. Software expected in Q4 2026. 2.If the DTC is in the N80 SCCM AND the following DTC's are in N30/3 (Electronic Stability Program) and N68 (Electric Power Steering): • N30/3 ESP: U071286, Steering column tube module control unit has a malfunction. There is an incorrect signal. • N68 EPS: U042986, Implausible data were received from the steering column module. There is an incorrect signal. Please open a TIPS case to the Body/Chassis/Entertainment inbox.
LI54.10-P-080288
Service Bulletin/Repair Instructions
Complaint The check engine light illuminates or the 48 V message is displayed in the instrument cluster Cause Fault code "P0A7F00" stored in the 48 V battery G1/3 and/or is current. Remedy 1. Check the SOHc of A66 48V battery. (For SOHr, see LI54.10-P-080199) 2. Carry out SOHc reset routine: - Switch on ignition - Read actual value 209 in XENTRY Diagnostics at G1/3 (48 V battery) "State of Health Capacity-SOHC" Valid for OBD markets -- If the value is > 80%, no restoration process required -- If the value is < 81%, continue with the following steps - Discharge Powerpack in vehicle - At SOC < 25%: Stop discharge and bring vehicle to sleep - >1.5h after vehicle sleep: Start engine and charge Powerpack to SOC >65% - At SOC > 65%: Stop operation and bring vehicle to sleep - >1.5h after vehicle sleep: Turn ignition on - Read Diagnostic Service C0C3 (State of Health Capacity - SOHC): if - Capacity > 74%: You can clear fault memory. Procedure finished. - Capacity < 74%: Repeat step 7 again. If after 2 repetitions value is still too high: Read diagnostic service FEE0 - FEE7 (Battery Analysis Protocol Part 1-8) and replace 48V Powerpack.Perform capacity restoration procedure: Valid for OBD markets - SOH > 82%: Process is complete and clear fault memory - SOH < 83%: Repeat the steps once more. If the value is still too low after 5 repetitions: Cancel healing process and provide feedback in TIPS case to the HV/LV team inbox labeled "SOHc cannot be reset"
LI27.19-P-080219
Service Bulletin/Repair Instructions
Complaint Check engine light on with the following fault is current in the VGS Control Unit: P084300 Oil pressure sensor 'A' has a short circuit to positive stored in VGS control unit. Cause Electrical failure of oil pressure sensor integrated into VGS Control Unit Remedy Intelligent Predictive Repair (IPR) recognizes this fault pattern and will provide the necessary repair suggestion. 1. Perform IPR and follow the recommended procedures 2. Replace complete EHS valve body, fill to near max fluid level, & complete initial start-up - Ensure all oil guide pipes are installed in the new valve body to prevent a new concern after replacement.
LI27.10-P-075869
Service Bulletin/Repair Instructions
Complaint Only vehicles with a variable transfer case are affected. This can be identified through control unit N45 or N15/7 in the quick test. When accelerating with light load, vibrations or jolting sensation may come from the drivetrain. It may be mistaken for a harsh shift. Cause Modified oil quality of the transfer case over time Remedy 1. Check initial quick test for faults in the following control units. N45 or N15/7 - All-wheel drive (ARS) N127 - 'Drivetrain' (PTCU) control unit Y3/8 - Transmission control for 9-gear transmission (VGS) N3/10 - Engine electronics for combustion engine If faults are present: Process them as per the guided test in Xentry. If no faults are present: 2. Check the transmission oil level If the oil level is correct: 3. Unplug the connector for the transfer cases control unit and reassess the vehicle on a subsequent test drive If the complaint no longer occurs with the control unit disconnected: 4. Perform an oil change of the transfer case according to WIS specifications - Collect an oil sample of the original fluid 5. Complete all transfer case Tech-in processes located under VG Control Unit > Adaptations - Resetting the oil service data - Calibration of N15/7 5. Perform road test of vehicle to bring transmission to operating temperature ( >60C ) 6. Operate vehicle in full circle with steering at full lock - 5x to the left - 5x to the right Return the vehicle to the client and request they drive the vehicle for at least 200 miles and return if the concern is not resolved. The extended drive will ensure the clutches are properly conditioned with the new oil and should resolve the concern. If the concern continues to occur with the control unit disconnected or after the above steps have been performed, please submit a TIPS case to the Powertrain inbox with the following information: - Initial quick test with fault freeze frame data - Initial transmission EEPROM data - VGS and Transfer Case Control Unit Log (N45 or N15/7) - Photo of the original oil condition - What color was the fluid drained from the transfer case before the oil change? - Was an oil sample collected, and can you provide a photo of the original fluid? - What color and part number fluid was used during the oil change? - How far was the vehicle driven after?
LI54.71-P-080236
Service Bulletin/Repair Instructions
Complaint Red ring displayed around vehicle when front or rear camera door actuates. Please also see LI54.65-P-080132 for additional listed red ring causes. Cause EMF interference. Remedy Camera functionality is not affected. Cameras and displays operate normally. For vehicles with a front facing actuating camera and flap (223 and 297): • 223, 297 > Install clip on ferrite magnet on M35/1, pin 3. For vehicles with rear facing camera (223, 213 Facelift, 238, 257, 290, 297): • 297 > Install 2 x ferrite magnets on M35/2, pin 3 and 4. • 213 Facelift, 223, 238, 257, 290 > Install on M35/2, pin 4
CL - 2025120010
Other
An authorized Mercedes-Benz dealer will update the software for the battery management control unit in your vehicle, free of charge. Your vehicle must be brought to a dealership to complete the update.
NCU - 2025120010
Service Campaign
Mercedes-Benz AG, the manufacturer of Mercedes-Benz vehicles, has determined that on certain subject vehicles, the 48V battery control unit (48 V LIB) software does not meet current production specifications. A miscalculation of the 48V battery’s aging threshold may trigger a fault message in the instrument cluster. MBUSA will conduct a service campaign. An authorized Mercedes-Benz dealer will update software in the 48V battery control unit (48 V LIB).
LI83.30-P-079850
Service Bulletin/Repair Instructions
Complaint Customer states the AC either does not cool/has poor performance or heat is insufficient. Cause Many possible root causes Remedy *Note - This Li does not apply if there are other Li's that apply to your concern OR you have a fault and/or guided test that leads to a root cause. AC Diagnosis (General) Initial Steps Verify Customer Concern • Confirm the issue reported by the customer. Compare to Like Vehicle • Determine if the behavior is normal by comparing with a similar vehicle. Determine Your Game and Players • Identify the diagnostic strategy and involved components/systems. Testing • Perform relevant diagnostic tests. Refrigerant Quantity • Record the amount of refrigerant recovered and compare it to the specified value (if applicable). • Forming Gas is the ONLY approved leak test method. (DYE is NOT approved) TIPS Case Submission Requirements/Warranty Claim Submission Requirements (Template attached to be used for submission of Warranty claim and/or TIPS case) Cooling Capacity Test (If System Has a Charge) *Note - TIPS case is only required if the root cause is not identified or other Li's/documents require a case to be open. Before Repairs Gauge Readings • High and Low pressure readings (from machine or separate gauges). Leak Detection (if applicable) • PPM of any leaks found. XENTRY Printouts • Climate control AVs. • HV compressor AVs (for heat and AC systems). Thermometer Readings • Left and right dash vents. • Center vent, footwell, and/or rear vents (if concern is localized). Ambient Conditions • Temperature and humidity from OCP AVs (if available). After Repairs Gauge Readings • High and Low pressure readings before and after repairs. Thermometer Readings • Left and right dash vents before and after. • Center vent, footwell, and/or rear vents before and after (if localized concern). Documentation • Complaint Analysis, Game/Players, and Testing Steps. • Include expected results and technical justification for the diagnosis. • Avoid listing R/I steps—focus on diagnostic reasoning and root cause. • All prior measurements need to be documented on the repair order. OP code usage: 831232 - Max .5 for Cooling Capacity Test 831040 - Only to be utilized if you have a fault code and are actively diagnosing that fault code (MAX 1 hour) 831762 - This includes basic leak check 831285 - This can only be used in extenuating circumstances where a leak cannot be found (MAX 1 hour)
LI05.20-P-080192
Service Bulletin/Repair Instructions
Complaint Customer states check engine light on in the dash. Vehicle has one or more DTC's Present P164B00, P164B09, P2B4400, P005A07, P005C07, P005A09, P005C09, P003C07, P2B5007, P003C09, P2B5009, P34C200, P34C109, P34C800, P34BE00, P34BD09 Cause Software and Hardware Remedy 1. Check for available Software updates for the Engine Control Unit ME N3/10. Perform update if available. 2. Check part numbers on ALL CAMTRONIC actuators to ensure latest part numbers are installed. 3. A177 982 03 03 and A177 982 17 00 should be replaced by A177 982 19 00 4. A177 982 02 03 and A177 982 16 00 should be replaced by A177 982 18 00 5. Remove engine cover and check for heat damage on the engine cover and wiring harness in the area above the engine compartment bulkhead and near the windshield. 6. In the event of wiring harness damage please open a TIPS case with photos of the harness and include a Lambda Line Graph Test for evaluation.
LI54.10-P-080199
Service Bulletin/Repair Instructions
Complaint For the potentially affected vehicles, excessively high aging of the battery was calculated at cold battery temperatures (<10°C) and the MIL activated accordingly, even though there is no corresponding high level of aging physically. In this regard, the fault code P0A7F00 "The age limit of the hybrid/high-voltage battery module has been reached" is displayed in the N127 PTCU control unit and/or A66 battery module control unit (48 V battery). Cause Faulty computation of the age limit of the 48 V battery. Remedy Step 1: Software update of A66 battery module (48 V battery) Step 2: Perform reset routine: 2.1 Read out actual value 056 in A66 control unit (age limit SOH-R) a. If SOH-R <= 125%: Delete fault memory in PTCU control unit (N127) and 48 V battery (A66). Process ended. b. If SOH-R > 125%: Drive for 60 min to add SOH-R value. 2.2 Read out actual value 056 in A66 control unit (age limit SOH-R) a. If SOH-R <= 125%: Delete fault memory in PTCU control unit (N127) and 48 V battery (A66). Process ended. b. If SOH-R > 125%: Park vehicle > 12 hours in the workshop at a warm ambient temperature > 15°C, then drive for 60 min. 2.3 Read out actual value 056 in A66 control unit (age limit SOH-R) a. If SOH-R <= 125%: Delete fault memory in PTCU control unit (N127) and 48 V battery (A66). Process ended. b. If SOH-R > 125%: Create TIPS case
LI27.35-P-080160
Service Bulletin/Repair Instructions
Complaint (Original LI document #: LI27.35-P-079039) Clicking noises from the electro-hydraulic control unit (EHS) when the vehicle is stationary and ECO Start/Stop is active (combustion engine is off). The noise is more noticeable outside the vehicle and in acoustically shielded areas such as closed rooms or garages. Cause The noise in the valve body (EHS) is caused by superimposed pressure peaks acting on the valves. This phenomenon occurs only after a certain running-in period due to the influence of micro-contamination in the valve bores. Remedy A hardware modification of the electro-hydraulic control unit (EHS) is currently being implemented (no change to the part number). This will be incorporated into series production and as a spare part starting from 12/2025. This is only a comfort-related complaint and has no impact on the functionality or service life of the transmission. For sensitive customers, the following measures can be performed: 1. Replace the electro-hydraulic control unit (EHS), the oil pan, and the transmission fluid. - Ensure all oil guide pipes are installed in the new valve body to prevent a new concern after replacement. (See attached location guide)
LI47.70-P-076030
Service Bulletin/Repair Instructions
Complaint After the charging process is complete, an instrument cluster message with a charging error appears and FC P0CFE00 is stored in control unit "N83 - AC charger for high-voltage battery (SG-LG)". The fault message and the fault memory entry can also appear at the beginning of the charging pause during delayed charging. Both only occur in combination with active pre-entry climate control. Cause Software in control unit "N83 - AC charger for high-voltage battery (SG-LG)". Remedy For model series 167, 214, 254 and 223 with code 802: Perform SCN coding in control unit "N83 - AC charger for high-voltage battery (SG-LG)". Please do not replace any parts even if the FC P0CFE00 coding continues to appear after successfully completing this step. A new software is currently in development and will become available in late 01/2026. Replacing parts will not remedy the issue. For model series 243: The correction is already available. Please inform the workshop to perform a software update and SCN coding for the control units "N116/5 - Direct current charging connection unit (DCCU)" and "N83/11 - AC charger for high-voltage battery (SG-LG)" in order to remedy the problem.
LI54.65-P-066284
Service Bulletin/Repair Instructions
Complaint The flap of the reversing camera opens and closes by itself during forward travel several times during the trip. No camera image is displayed in the head unit. The reversing camera or the 360° system functions normally when activated manually or by engaging drive range "R". Cause This is not a malfunction, but an intended system behavior. Calibration of the reversing camera is in progress. The calibration is completed by: • Opening the camera cover for a maximum of 5 cumulative minutes. • If the vehicle speed is < 35 km/h (<22 MPH). • The steering wheel angle is < 10°. If calibration is aborted by exceeding one of the above conditions, the camera retracts and the calibration will re-attempt once the conditions are achieved and the speed returns to the range of 18 km/h (~11 MPH). Remedy SCN code PARK213M on MFA2 facelift vehicles produced after 09/2024 (A-Class, CLA, GLA, etc...) so the complete calibration speed window is available. For vehicles with PARK213M or PARK223 a calibration is completed successfully by: • Driving forward (typically less than 1 minute). • Vehicle speed is < 35 km/h (<22 MPH). • The steering wheel angle is < 10°. • During daylight. • Without a vehicle following too closely (camera must be able to see asphalt). When calibration has completed successfully, the camera door closes automatically for the rest of the driving cycle. The camera will now only open if the customer requests (Example: Engaging reverse gear). The calibration of the camera will re-initiate every drive cycle (ignition change). The customer can generally perform calibration at the first attempt while briefly maintaining a speed range of 15 km/ h (~9 MPH) and 35 km/h (~22 MPH). The customer can therefore play a significant role in reducing the camera door noise and actuation frequency.