PE22012 · PE
SERVICE BRAKES, HYDRAULIC:ANTILOCK/TRACTION CONTROL/ELECTRONIC LIMITED SLIP:CONTROL UNIT/MODULE Investigation
The Office of Defects Investigation (ODI) opened this investigation on November 28, 2022, after receiving 134 reports from consumers alleging an intermittent or permanent loss of braking performance in certain 2017-2018 Ram 2500-3500 pickup trucks manufactured by Fiat Chrysler Automobiles (FCA). The alleged failures continued to occur at a steady rate across both models, at all speeds, with limited detectability. Consumers complained that the Anti-lock Braking System (ABS) warning light illuminated on their vehicles. The ABS module works in conjunction with the Hydraulic Control Unit (HCU), an electromechanical device that controls hydraulic pressure to the individual wheel brake assemblies, to manage braking forces during emergency stops. During this investigation, ODI received over 2,500 consumer complaints concerning ABS or HCU warning lights that illuminated on the dashboards of their vehicles. Many consumers described also having trouble with cruise control, traction control, or electronic stability control. Of the complaints received, over 50% mentioned that the ABS or HCU warning light was intermittent in nature. ODI learned that in January 2021, FCA was aware of a problem with the ABS pump motors on the subject vehicles. FCA had been working with the supplier, ZF, on an issue concerning swelling of the brushes inside the motor. According to a briefing given by ZF to FCA on January 15, 2021, the ABS, electronic stability control (ESC), traction control system (TSC) and other functions utilizing the motor would be disabled in the event of a problem with an ABS pump motor. ZF also informed FCA that Slip Control would be inhibited with the driver warning lamp illuminated, base braking would not be affected, and FMVSS stopping distance requirements would still be met. In order to better understand the potential consequences of the brushes swelling and the disablement of the ABS, ESC, TSC and other functions, ODI requested that NHTSA's Vehicle Research and Test Center (VRTC) conduct testing on a subject vehicle with a faulty pump motor installed. During the testing, VRTC found that as the brushes started to swell in the motor, the warning lamp could illuminate intermittently, causing confusion to drivers. Although the warning light illuminated intermittently, VRTC discovered that the pump was not working properly regardless of the warning light status. In this condition drivers might think that their vehicle is operating normally when the warning light is off, but instead, the ABS, ESC, TSC and other functions supported by the pump will not work. Following a series of meetings with FCA to demonstrate the findings ofVRTC's testing, FCA conducted an internal review and on November 27, 2024, FCA submitted safety recalls 24V-896 and 24E-100. In view of the recalls being conducted by FCA, ODI has closed this Preliminary Evaluation. The Agency reserves the right to take additional action if warranted by future circumstances. To review the ODI reports cited in the Closing Resume ODI Report Identification Number document, go to NHTSA.gov.
PE18016 · PE
STEERING:LINKAGES:DRAG:LINK:CONNECTION Investigation
On December 17, 2018, NHTSA's Office of Defects Investigation (ODI) opened Preliminary Evaluation (PE) 18-016 to investigate the steering system on model year (MY) 2015 and 2016 Ram 2500 manufactured by FCA US, LLC (FCA). Four complaints were received alleging separation of the drag link, a steering linkage that connects between the right front steering knuckle and the pitman arm on the steering box output shaft. The failures were found to be at a threaded coupler within the drag link used for adjusting the length of the linkage during routine maintenance (alignment) of the steering system.Once separation occurs, turning the steering wheel has no effect, and there is no way for the driver to control or maintain the direction of the vehicle. During the investigation, it was determined that the same threaded coupler was used on two different drag link designs FCA manufactured on MY 2013-2018 Ram 2500 and 3500 pickups. FCA refers to the designs as either 4x2 or 4x4 style. In both designs, the coupler is prevented from turning on the drag link via two jam nuts that are tightened against the coupler. In its response to NHTSA's March 15, 2019, Information Request (IR) letter, FCA identified 48 incidents alleging separation of the steering linkage at the coupler resulting in a loss of steering control. Of those, 13 involved a crash, one of which resulted in an injury. All of the separations involved the 4x4 style drag link. Additionally, FCA's IR response refers to over 300 4x4 style equipped vehicles that experienced, or may have experienced loosening of one or more coupler jam nuts. On January 25, 2019, FCA submitted a Defect Information Report (DIR) initiating NHTSA Recall No. 19V-021. In its DIR, FCA stated that the outboard jam nut in certain MY 2013-2018 Ram 2500 and 3500 could loosen potentially resulting in damage to the coupler and/or drag link threading allowing one end of the drag link to separate. The DIR notes that drag link separation results in loss of steering control, which in turn can cause a crash without warning. FCA's DIR did not identify a root cause for the defect, however it posits that an improperly torqued outboard jam nut could loosen, and with long-term vehicle use, cause damage to the outer link bar and/or coupler threads due to relative motion between the two components. The scope of Recall 19V-021 included vehicles with the 4x4 style drag link only. Also discussed in its IR response, FCA noted that the 4x2 style drag link contains a design difference (the outboard portion of the drag link is straight while the 4x4 style contains a bend) which it suggests may result in differences in the mechanical (bending) loads presented at the coupler and jam nut interface. Moreover, the DIR states that While root cause of the 4x4 style defect has not been established, FCA US believes that bending loads on the drag link is, at least, a causal contributing factor. FCA notes it did not identify any reports alleging 4x2 style separation as well as only three reports of loosening of jam nuts, two of which resulted in loosening that provided obvious warning to the vehicle operator, indicating a different failure mode.NHTSA is upgrading this investigation to Engineering Analysis (EA) 19-004 in order to continue to monitor the subject 4x2 style vehicles for evidence of field failures. Additionally, in conjunction with NHTSA's Vehicle Research and Test Center, ODI intends to more thoroughly study potential root cause(s) of the 4x4 style defect mechanism, and if identified, will seek to determine if the 4x2 drag link is susceptible to the same mechanism(s). NHTSA will also evaluate the long-term suitability of the recall