Acura TLX Investigations

5 ODI actions on file.

• DPDP26001CLOSEDOpened 3/6/2026
  All wheel drive allegation
  POWER TRAIN:AUTOMATIC TRANSMISSION

  The Office of Defects Investigation (ODI) has completed its review of a Petition dated January 9, 2026, requesting an investigation into the loss of the optional all-wheel drive capability in model year (MY) 2021-2023 Acura TLX and MY 2022-2023 Acura MDX vehicles. The Petition alleges failures in the interfacing splines between the front wheel drive transaxle and the rear wheel drive power take off unit. Failure of these splines prevents the transfer of drive power to the rear axle, making the vehicle front wheel drive only. The Petition further alleges that this failure reduces vehicle directional control. Most traditional AWD systems utilize mechanical and passive measures. These systems have the tendency to distribute torque along the path of least resistance, such as a wheel that has lost contact with the ground or is on a low friction surface such as ice. To compensate for this, many manufacturers use the brake system to redirect torque to the wheels with more traction.  However, in this style of AWD system, a failed drive shaft or similar disconnection prior to the brakes often results in drive power being lost to the disconnected component. The consequence of this loss is the inability to maintain speed with surrounding traffic which increases the risks of collisions and injuries to the vehicle occupants. The Subject Vehicles are built upon a platform that was designed primarily as Front Wheel Drive (FWD). The SH-AWD system functions more as a performance enhancement feature rather than a stability feature. Even if the SH-AWD is nonoperational, the vehicles retain full mobility via FWD. In addition, the Vehicle Stability Assist (VSA) remains functional, ensuring directional stability through traditional engine and brake-based traction control. Although the condition raised by the Petitioner may degrade the vehicle’s performance characteristics, there is insufficient information to indicate a potential unreasonable safety risk. ODI reviewed 62 Vehicle Owner Questionnaires (VOQs) and several EWR Field Reports alleging the loss of SH-AWD and its impact on the driving dynamics of the subject vehicles. During its analysis, ODI determined that the failure is localized to the mechanical interface between the FWD transaxle and the PTU. Specifically, the failure is the shearing or stripping of the interfacing splined shafts between the FWD transaxle and the PTU, resulting in a permanent loss of torque transfer to the rear of the vehicle. Upon reviewing the technical details of SH-AWD, ODI has found that this failure does not result in any loss of motive power or lead to a loss of vehicle control. Several complaints indicated that the operators were unaware of the mechanical fault until encountering a low friction surface or the condition was identified by a technician during routine maintenance. The SH-AWD system lacks any form of direct feedback for monitoring real time torque transfer to the rear wheels. Therefore, the system will continue to display information indicating power is being supplied to the rear wheels even when power is actually only supplied to the front wheels. ODI’s review did not identify sufficient evidence to indicate that the misinformation has presented a safety issue in the field. ODI did not identify any reports of loss of motive power or vehicle control that could be attributed to the loss of SH-AWD. ODI is not aware of any crashes involving the Subject Vehicles that resulted from the loss of SH-AWD. After thoroughly assessing the material submitted by the Petitioner, consumer complaint information in NHTSA’s databases, and other relevant information already in possession of the Agency, NHTSA has not found sufficient evidence to indicate that the loss of AWD as alleged by the Petitioner is likely to present a safety related defect that would warrant a formal investigation. After full consideration of the available information, and in view of NHTSA’s enforcement priorities, the Petition is denied.  A denial report will be posted in the Federal Register.  The closing of the petition does not constitute a finding by NHTSA that a safety related defect does not exist, and the agency reserves the right to take additional action if warranted by future circumstances.  The Petition can be viewed at NHTSA.gov under ODI Number 11712885.

• PEPE25008OPENOpened 8/20/2025
  Engine failure
  ENGINE

  The Office of Defects Investigation (ODI) has received 414 reports of connecting rod bearing failures in the 3.5L V6 engine used in the following vehicles: Model Years (MY) 2018-2020 Acura TLX, MY2016-2020 Acura MDX, MY2016-2020 Honda Pilot, MY2018-2020 Honda Odyssey, and MY2017-2019 Honda Ridgeline.  The subject engine failures were analyzed as part of a Recall Query (RQ24013).  It was determined that these engine failures are outside the scope of Honda Recall 23V-751. Further, evidence gathered in conjunction with RQ24013 does not suggest this failure is caused by the same crankshaft manufacturing defect that is addressed by Honda in Recall 23V-751.  Based on analysis of data from RQ24013, NHTSA has closed that investigation. The significant number of reports of engine failure in vehicles outside the scope of RQ24013 presents a potential safety risk that warrants further investigation.  ODI is opening this Preliminary Evaluation (PE) to further evaluate the scope and severity of the potential problem and to fully assess the potential safety-related issues.  To review the ODI reports cited in the Opening Resume ODI Report Identification Number document, go to NHTSA.gov.

• EAEA25004OPENOpened 3/26/2025
  No Restart After Auto Start/Stop Engages
  ENGINE AND ENGINE COOLING:ENGINE:CRANK/CAMSHAFT POSITION SENSOR

  On June 3, 2022, the Office of Defects Investigation (ODI) opened Preliminary Evaluation PE22005 after the agency received VOQs and several field reports concerning the Auto Idle Stop (AIS) feature on 2016-2019MY Honda Pilot vehicles. The complaints allege that the engine fails to restart on its own from a complete stop at a traffic light or road intersection with the AIS function engaged. The subject vehicles are equipped with a 3.5L engine with a 9-speed automatic transmission. On January 6, 2023, Honda released service bulletins 23-008 and 23-009. These service bulletins address the failure to restart issue in the 2016-2019MY Honda Pilot vehicles, as well as the 2015-2020 Acura TLX, 2016-2020 Acura MDX, 2019-2022 Honda Passport, and 2020-2023 Honda Ridgeline vehicles. The repair outlined in the service bulletins is a two-stage countermeasure to remedy the issue. The first stage is a Programmed Fuel Injection (“PGM-FI”) software update. The second stage is only deployed if the software update fails to remedy the issue. The second stage, depending on the model and model year, consists of replacement of the starter assembly, starter relays, and a valve adjustment. Additionally, Honda extended the warranty coverage to 10 years with unlimited mileage for vehicles requiring the second stage component replacement. ODI continues to receive complaints of the AIS failure to restart, with many complainants alleging the campaign countermeasures had been completed.NHTSA has reviewed Honda's Information Request Letter responses involving warranty claims, lawsuits, and consumer complaints in addition to ODI's own data. This Engineering Analysis is being opened to further consider the potential safety defect, including gathering additional data regarding Honda’s service campaign efficacy. ODI is additionally expanding the scope to encompass all vehicles addressed in Honda’s service bulletins 23-008 and 23-009 as well as newer model year vehicles, which are substantially similar to the vehicles covered by the service campaign. To review the ODI reports cited in the Opening Resume ODI Report Identification Number document, go to NHTSA.gov.

• RQRQ24013CLOSEDOpened 11/8/2024
  Engine failure
  ENGINE

  On November 8, 2024, the Office of Defects Investigation (ODI) opened Recall Query RQ24013 to assess the scope of Honda recall 23V-751 after receiving complaints that alleged connecting rod bearing failures in vehicles that were not within the scope of recall 23V-751. In November 2023, Honda recalled 248,999 various Model Year (MY)2016–2020 Honda and Acura vehicles equipped with the 3.5L V6 engine. Honda recalled these vehicles due to a crankshaft manufacturing defect that caused premature connecting rod bearing wear and engine seizure. While the out-of-scope failures involved in these complaints appear to have a very similar failure mechanism as the recalled engines, a thorough analysis of all available data from Honda has not indicated that the same manufacturing defect exists in the out-of-scope engines as the engines recalled by 23V-751. Based on this analysis ODI has determined that Honda has properly defined the scope of recall 23V-751. Consequently, ODI will close this RQ investigation.  NHTSA will continue to investigate these complaints of engine failure as part of a new Preliminary Evaluation Investigation (PE25008). The Agency reserves the right to take additional action if warranted by new circumstances.

• EAEA19001RECALLOpened 4/19/2019
  Electrical overstress
  AIR BAGS: AIR BAG/RESTRAINT CONTROL MODULE

  The Office of Defects Investigation (ODI) opened this investigation to determine if the failure of airbags to deploy during severe crashes, in certain vehicles, was the result of a safety related defect.  During the investigation a complex failure was studied that can result in non-deployment of subject vehicle air bags and other restraint system devices in severe crash events. The subject vehicles may be equipped with an airbag control unit (ACU) for the supplemental restraint system (SRS) Electronic Control Unit (ECU) manufactured by ZF-TRW.  The ECU receives signals from crash sensors mounted in the vehicle and deploys the vehicle air bags and seat belt pretensioners in accordance with manufacturer design specifications.  The ECU in the subject vehicles contains a model DS84 application-specific integrated circuit (ASIC) which controls the communication of the crash sensor signal, firing commands (i.e., when to deploy the airbag(s) and/or pretensioners), and fault information (e.g., diagnostic trouble codes). In September 2016, FCA announced recall 16V-668 for certain model year (MY) 2010 to 2014 Chrysler, Dodge and Jeep products manufactured with the subject ZF-TRW ACU.  In this recall, FCA discussed an EOS condition that resulted in a failure of the subject DS84 ASIC, which caused air bag non-deployment.  FCA noted that the defect condition had only been observed in vehicles equipped with sensor harnessing routed across the front of the vehicle.  Other FCA vehicles that also used the subject ACU, but were not equipped with cross-car harnessing, had not experienced EOS failures, despite similar time in service. During the course of this investigation, ODI sent two separate Information Request (IR) letters to six vehicle manufactures (including FCA, Hyundai, Honda, Kia, Mitsubishi, and Toyota) and one IR letter to ZF-TRW.  These IR letters resulted in ODI receiving comprehensive data from these manufacturers and suppliers. Studies of this data found that the DS84 ASIC does not have sufficient protection against negative electrical transients or electrical overstress (“EOS”) that can be generated in certain severe crashes.  An electrical transient occurs when the electrical power supplied to a circuit changes momentarily over a short duration of time.   In these severe crash cases, the crash sensors and other powered wiring can be damaged and short circuited so as to create a negative electrical transient of sufficient intensity and duration (that are outside the vehicle manufacturer's specification) to damage the ASIC before the restraint device deployment signal is received by the SRS ECU.  This damaged signal can lead to incomplete or nondeployment of the air bags and/or pretensioners.  Airbag non-deployment and/or lack of pretensioner operation can increase the risk or severity of injury in a crash.A total of 8 fatalities and 14 injuries were associated with known EOS events. The common element in all investigated manufacturers vehicles is the SRS ECU containing a DS84 ASIC manufactured by ZF-TRW.  The risk associated with the ASIC is equally shared among all OEMS involved in the investigation.  The actual real-world risk can be mitigated by other factors which were assessed by ODI during this investigation. The first mitigating factor involves protections built into the ACU design which protect the DS84 ASIC from damage.  There are multiple strategies and levels of protection employed by different OEMs that provide effective EOS mitigation.  The two most common strategies at the ACU level are circuit protection diodes on the remote senor signal lines, and current limiting resistors that protect critical components. The second mitigating factor is found at the vehicle level and involves the location and routing of the wires leading from the crash sensors to the SRS ECU.  If the wires are well protected in a crash and are not routed with other power wires carrying large currents, the risk for an EOS event is significantly reduced or eliminated. These design specific factors combine to produce a spectrum of risk for the vehicles equipped with ACUs using the DS84 ASIC.  Given the many of years of field exposure, it is possible to divide the subject population into two groups; vehicles which have experienced EOS events, and vehicles which have not experienced EOS field events. Four of the six OEMs involved in this investigation have experienced EOS field events on at least one of their models equipped with a DS84 ASIC.  All vehicle models (including the Toyota models identified in the Failure Report Summary of the opening resume for this investigation) with field events have been recalled.  In an abundance of caution, ODI kept this investigation open five years to monitor field performance and did not identify any field events on vehicles not included in existing safety recalls. Given the spectrum of risk identified in this investigation and that all vehicles with a demonstrated unreasonable risk have been recalled, ODI is closing this investigation. ODI is closing this investigation with the following manufacturer safety recalls: 16V-668, 18E-043, 18V-137, 18V-363, and 20V-024.  With the recall actions taken by the subject vehicle and equipment manufacturers, this investigation is closed. The closing of this investigation does not constitute a finding by NHTSA that a safety-related defect does not exists on other model or model year vehicles outside of the recall scopes. The agency reserves the right to take further action if warranted by the circumstances.