2021 Acura TLX

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.

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.

I'm losing power than normal all of a sudden. When I step on the gas after light hits green in sport and sport plus mode my car losses traction even when traction control is on, and I hear a loud clunck sound. After the the loud clunck sound the car losses RPM while driving I step off the gas and step back on it and the RPM goes back to normal again.

NHTSA ID

11754848

Incident

Aug 4, 2026

I took this vehicle to get serviced in the summer of 2025. I recently joined an Acura Type S (2021+) group on Facebook and learned that the issue is quite prevalent. I had to have the transmission and transfer case replaced due to transmission issues and traction issues

NHTSA ID

11750163

Incident

Jul 5, 2025

On July 7th 2026 I was driving home, came to a stop light at normal speed, when the light turned green I took off at normal speed and I heard a huge cluck / bang from underneath the car and it bogged and didn’t want to move. I then stepped on the gas because of the Car behind me getting to close and my traction control light started to flash and the car started to shake and feel very uncomfortable to drive . After that I realize only the two front wheels of the car were working and even at low cruising speeds the car feels very unsafe and shakes and hear noises I never heard before the part that is causing this is the transfer case and transmission thus there are many other people who have had this same issues ranging from 21 to 23 tlx type s with 15k miles to 100k miles

NHTSA ID

11748958

Incident

Jul 7, 2026

Transmission splines went out and transfer case has also failed which is only sending power to front wheels

NHTSA ID

11748927

Incident

Jul 6, 2026

On 07/01/2026, at approximately 8:00 AM, during steady acceleration, flashing of MIL with loss of power presented northbound after merging from 235 west bound to I-135 north bound near Park City, KS. Particularly dangerous resulting in near rear end collision. Upon taking nearest exit ramp, attached BlueDriver .OBD II reader, and fault code P0303 - Cylinder 3 Misfire and U0401-68 PGM-Fi/ECM/PCM system event code was logged, with multiple warning indicators that safety system, AWD, brake, and other systems were disabled. Note, vehicle has had TSB 20-053 update w/ flash of PGM-Fi which did not resolve the fault, fault associated with hot and humid climates or period of rain fall, apparent water vapor, condensate build up in intercooler. For Honda Accord and Acura RDX w/ 4 cylinder 2.0 TDGI engine TSB includes redesigned intercooler replacement, that is not available for TLX 21-25 which is currently out of production. This has occurred previously during humid and hot weather, but no intermittent flashing MIL does not store code. Thankful in this instance P0303 and U0401-68 code is stored, and scheduling service at dealership to diagnose misfire.

NHTSA ID

11747673

Incident

Jul 1, 2026

2021 Acura TLX Type S SH-AWD. Total mechanical failure of PTU/transfer case spline interface at 29,800 miles within factory powertrain warranty. Vehicle operated silently in FWD-only with no warning lights, no fault codes, and no dashboard alerts — consistent with all complaints cited in NHTSA Defect Petition DP26001 (opened March 6, 2026, NHTSA #11712885). Failure confirmed by dealer via lift test: propeller shaft and rear wheels stationary while fronts spun. During actuator test, Check AWD System light illuminated for the first time — because the lift removed road-induced wheel rotation that had masked the failure from the ECU throughout normal driving. This is the only condition under which this failure mode is electronically detectable. Dealer replaced transmission (remanufactured ATR kit) and PTU under warranty. Repair took 38 days. CRITICAL-THIRD PTU REVISION: Replacement PTU installed was part #29000-5YK-070. Known revision history: -050 (original, confirmed failure part) → 060 (revised ~2022) → 070 (installed June 2026). The 070 does not appear in any public OEM parts database. Acura has now revised this component three times with zero TSBs, zero public disclosure of engineering changes, and no recall. The 070 revision appearing after DP26001 opened in March 2026 suggests a silent root cause fix while avoiding formal recall obligations. CRITICAL-DPSM GOODWILL CLAUSE: Acura required acceptance of "One Time Goodwill Authorized by DPSM" as condition of repair. This was a warranty obligation, not a goodwill gesture. This clause was imposed while DP26001 is under active federal review, before factory warranty expires, with no confirmed root cause fix. If the 070 part fails again, this clause may be used to deny future warranty coverage. Requesting: (1) complaint added to DP26001 record; (2) Acura compelled to disclose engineering changes between part numbers 050, 060, 070; (3) investigation of DPSM Goodwill clause as systematic pre-recall liability limiation

NHTSA ID

11743423

Incident

Apr 28, 2026

I am submitting this complaint in reference to NHTSA Defect Petition DP26001, opened March 6, 2026, investigating loss of all-wheel drive capability in 2021-2023 Acura TLX vehicles due to interfacing spline failure between the transmission and the power takeoff unit (transfer case). I am the owner of a 2021 Acura TLX SH-AWD with 55,300 miles. I purchased this vehicle on June 2nd, 2026. I have not yet experienced a failure, but I am registering as an affected vehicle owner given the known defect pattern documented in DP26001 and consistent with the 137,329-vehicle population identified in the NHTSA investigation. The failure mode as described in DP26001 involves stripping of splines at the transmission-to-PTU junction, resulting in sudden and complete loss of rear-wheel drive without warning lights or dashboard indication. Documented repair costs for this failure range from $5,000 to $19,000 depending on extent of damage. I am registering this complaint to be included in the documented owner population should the petition escalate to a formal defect investigation or recall. I request notification of any recall action, extended warranty coverage determination, or technical service bulletin issued for this failure pattern.

NHTSA ID

11741697

Incident

Jun 2, 2026

El problema es exactamente en el tanque de la gasolina, se está saliendo la gasolina en la unión de la manguera de llenado con el tanque de gasolina. Esto representa un riesgo no solo para mi seguridad sino también para cualquier persona.

NHTSA ID

11741431

Incident

Jan 4, 2026

Over The Air Update - Vehicles equipped with the System Updates application are capable of downloading and installing Over the Air System Updates. System Updates contain upgrades that fix a variety of operational errors and/or enhancements that add new functionality. Information for the various software releases can be found in this document. Software version: D.1.6.4

Service Bulletin - Oil leak at the cam chain tensioner inspection cover due to and insufficient sealant adhesion on the inspection cover.

Dealer Message - American Honda Motor Co., Inc. (AHM) is searching for certain 2022- 2024 MDXs & 2021-2025 TLXs with a client complaint of a loose or detached rearview mirror bracket. To better understand the cause of this condition, AHM would like to collect specific parts from the vehicle prior to you attempting a repair of any kind.

Dealer Message - American Honda Motor Co., Inc. (AHM) is searching for certain 2021-2023 TLX ADV’s and 2021-2025 TLX Type S’s with a client complaint of the “Adaptive Damper System Problem” (ADS) error message on the MID (Multi Information Display). To better understand the cause of this condition, AHM would like to collect specific parts from the vehicle prior to you attempting a repair of any kind.

Dealer Message - American Honda Motor Co., Inc. (AHM) is searching for certain 2021-2023 TLX ADV’s and 2021-2025 TLX Type S’s with a client complaint of the “Adaptive Damper System Problem” (ADS) error message on the MID (Multi Information Display). To better understand the cause of this condition, AHM would like to collect specific parts from the vehicle prior to you attempting a repair of any kind.

Dealer Message - American Honda Motor Co., Inc. (AHM) is searching for certain 2021-2023 TLX ADV’s and 2021-2025 TLX Type S’s with a client complaint of the “Adaptive Damper System Problem” (ADS) error message on the MID (Multi Information Display). To better understand the cause of this condition, AHM would like to collect specific parts from the vehicle prior to you attempting a repair of any kind.