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.
M1490
Service Bulletin/Repair Instructions
SERVICE BULLETIN M1490 (V 26.8.3): DIGITAL TECHNICIAN II - UPDATES AND RELEASE NOTES. PURPOSE: Revision. This bulletin informs dealers that Harley-Davidson has made a software update to Digital Technician II (DT II). DIGITAL TECHNICIAN II (PART NUMBER: HD-48650). Version Version 26.8.3, Release Date: Week of July 24, 2026. NOTE: Software version (26.4.3) will need to be manually installed only if current software version of DT II is (26.0.2). After (26.4.3) is manually installed, automatic updates will bring DT II to the latest software version. Refer to bulletin M1713 for instructions. New Features - Harley-Davidson: 2023-2024 Touring: Updated Electronic Control Module (ECM) calibration offerings. LiveWire: S2DM/MH/AP: Calibration bundle 10.2.28: Telematic Control Unit (TCU) reflash updates. Change: Vehicle Setup: Body Control Module (BCM) – Tire Pressure Monitoring System (TPMS) Replacement: Correct issue where tire size selections were not available. System Info – Auxiliary Load Controller (ALC): Added Bike configuration field. Data Items – Trike ECM: Improved display of Gear Position when in reverse. Amp – Added support for (Part No. 76001619).
M1679
Service Bulletin/Repair Instructions
SERVICE BULLETIN M1679: AFTERMARKET EXHAUST HEADER DEBRIS. PURPOSE: Initial release. This bulletin informs dealers that Harley-Davidson has identified instances of premature engine failure due to abrasive particle wear, specifically from debris inside new aftermarket exhaust headers. Recent evaluations have identified that certain newly manufactured exhaust headers may contain residual hard particles that, if not removed prior to installation, can migrate through the engine system and cause accelerated component wear or severe mechanical damage.
M1713
Service Bulletin/Repair Instructions
SERVICE BULLETIN M1713 (REV C): DTII UPDATE PROCEDURE FOR SOFTWARE VERSION (26.4.3). PURPOSE: Revision C. This bulletin informs dealers that an issue was discovered in the Digital Technician II (DT II) software version (26.0.2), released on November 18, 2025. The issue prevents automatic software updates to be installed on your DT II computer. A manual installation of the latest DT II software version (26.4.3) will need to be performed if current DT II software version is (26.0.2), to allow future automatic updates. If a manual update to (26.1.5) or (26.3.2) has previously been completed, DT II will automatically update to (26.4.3) and no additional action is needed.. Revision C. Updated: Purpose for Service Bulletin and Required Dealer Action. Updated to Software Version (26.4.3).
W146
Warranty Program/Extension
WARRANTY BULLETIN W146 (REV C): TIRE TREAD DEPTH GUIDE-UPDATE. PURPOSE: [Revision C. Updated: Tire Tread Depth Guide. Add tire part numbers 43100063, 43200035,43100029A, 43100033A and 43200045A.] To provide tire tread depth specifications for the dealership network to consult when filling warranty claims on used tires. Please see the Warranty Manual of your region for tire policy guidelines.
M1391A
Service Bulletin/Repair Instructions
SERVICE BULLETIN M1391A (REVU): MIDTRONICS GRX-3110 AND DCA-8000 SOFTWARE. PURPORSE: Revision U. The purpose of this bulletin is to inform the dealer network that a software update to the GRX-3110 and DCA-8000 is now available. DYNAMIC DIAGNOSTIC CHARGER SYSTEM (PART NUMBER: DCA-8000). [Rev U] Added: Description of improvements made to the testing algorithm for GRX software Version P and DCA-8000 software Version E.
PAB1171
Service Bulletin/Repair Instructions
GENUINE MOTOR PARTS AND ACCESSORIES BULLETIN PAB1171 (REV B): SOFTWARE UPDATE FOR SCREAMIN EAGLE PRO STREET TUNER. PURPOSE: Revision B. Updated: Summary. The App has returned to the Apple App Store. This bulletin informs dealers that a recent software update to the Screamin' Eagle Pro Street Tuner application will require the use of a Personal Computer (PC) to complete a Bluetooth Communication Interface (BCI) firmware update.
M1684
Service Bulletin/Repair Instructions
SERVICE BULLETIN M1684: MARKET SPECIFIC BATTERY INTRODUCTION. PURPOSE: Initial Release. This bulletin informs dealers of the availability of new batteries for new Original Equipment (OE) vehicle production and in the Parts and Accessories (P&A) catalog. Availability of the new Absorbed Glass Mat (AGM) batteries will vary by market and will be transitioning over the next few months. NOTE: The ring terminal screws are not compatible between Leoch and East Penn batteries. The new batteries will include new ring terminal screws, which must be used. The ring terminal screws from the old battery need to be discarded.
M1555
Warranty Program/Extension
SERVICE BULLETIN M1555 (REV H): BATTERY WARRANTY GUIDELINES. PURPOSE: This bulletin informs the dealership network that Harley-Davidson has provided guidelines for battery warranty. REV H. Update section headers: AGM and Lithium-Iron Phosphate Batteries. Add graphics and callouts. Updated: Information on Battery.
PAB1165
Service Bulletin/Repair Instructions
GENUINE MOTOR PARTS AND MOTOR ACCESSORIES BULLETIN PAB1165 (REV A): H-D SYN3 SAE 15W50 / SAE 50 AVAILABILITY. PURPOSE: Revision (A) * Updated: Summary, Update table. This bulletin informs of the availability of the SYN3 New Improved Formula, a dual weight SAE 15W50 / SAE 50 Motorcycle Oil. The new formula transitions into inventory as the old SYN3 20W50 product inventory is depleted. Availability varies by SKU and region. The original SYN3 20W50 will be obsoleted when the transition is complete.
PAB1158
Service Bulletin/Repair Instructions
GENUINE MOTOR PARTS AND MOTOR ACCESSORIES BULLETIN PAB1158: OIL FILTER PACKAGING AND CASE QUANTITY UPDATE. PURPOSE: To inform dealerships that Harley-Davidson has made updates to oil filters including new part numbers, packaging design, and bulk case quantity changes.
PAB1144
Service Bulletin/Repair Instructions
GENUINE MOTOR PARTS AND MOTOR ACCESSORIES BULLETIN PAB1144: 2021-2022 SCREAMIN' EAGLE STAGE I (CARB) EO APPROVALS. PURPOSE: Revision. To inform California dealers about the new California Air Resources Board (CARB) approvals for select 2021-2022 Harley-Davidson vehicles. Summary: Various Screamin' Eagle Air Cleaner Kits and Stage I calibrations have been approved for sale on select 2021 and 2022 Harley-Davidson models. Please see the table below that indicates which part numbers should be ordered for what models. Revision: Refer to Summary. Update non-Bluetooth calibrations availability.
PAB1111
Service Bulletin/Repair Instructions
GENUINE MOTOR PARTS AND MOTOR ACCESSORIES BULLETIN PAB1111: 2021 VEHICLES - SCREAMIN' EAGLE UPDATES. PURPOSE: Revision. To notify dealers of Screamin' Eagle® Street Tuner 49-State (only) calibrations for 2021 vehicles are now available. Screamin' Eagle Smart Tune Pro Automatic Tuning Module is currently a no-fit for 2021 Softail, Touring, Custom Vehicle Operations (CVO) Touring, Police Touring or Trike models due to the 2021 Electronic Control Module (ECM) change. However, it will continue to work with 2021 Sportster models. The Screaminâ Eagle team is working on enabling this product to fit those Milwaukee-Eight® (MKE-8) equipped ECMs in the future.
M1520
Service Bulletin/Repair Instructions
SERVICE BULLETIN M1520: 2021 INITIAL CARE. PURPOSE: Revised. The purpose of this program is to monitor Harley-Davidson quality delivered to the customers. Harley-Davidson Technical Service is providing an initial care program for a number of 2021 vehicle components. Update: All Internal Combustion Engine (ICE) vehicles parts have been removed from the initial care program as of March 19, 2021. All Electric Vehicle (EV) parts will remain in the initial care program. Table 2, Initial Care Parts List. Duration of Program: January 4, 2021 through April 4, 2021.
TA0006
Service Bulletin/Repair Instructions
Harley-Davidson is aware of conditions that may result in a streaking appearance or film residue on the inside of some instrument gauges including speedometer and tachometers. This may occur after exposure of the vehicle to humid conditions. This condition may remain even after the moisture has evaporated.