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.

My 2021 Acura TLX has a fuel leak. This is a known issue and manufacture design flaw. The Acura dealership has quoted my $4200 - $4500 to replace the fuel tank. I've contacted Honda and they've only offer $300 "goodwill" credit towards the repair. This is a know issue, a fire hazard, and other 2021 TLX has been recalled for this fuel tank/fuel leak issue via recall.

NHTSA ID

11766764

Incident

Aug 29, 2026

I drive a 2021 Acura TLX TYPE S around 85K miles. I heard a loud clank when I was driving one day, and I loss traction. When I was accelerating I was losing traction and it seem like I lost power while I was moving as well. It seems like I'm driving front wheel drive. I let me foot of the gas and it seems like it's back to normal SH-AWD. I hope this gets looked into and fixed soon.

NHTSA ID

11763748

Incident

Sep 10, 2026

The transfer case and transmission splines have been stripped causing the car to be FWD only. The issue was confirmed by the dealer, and both the transfer case and transmission were replaced under warranty. The car shuddered, followed by a drivetrain noise for a few seconds. No warning lights or messages appeared when the incident occurred. The issue occurred at approximately 26,574 miles on the odometer.

NHTSA ID

11760565

Incident

Aug 17, 2026

transfer case leaking fluids at 73,000 miles

NHTSA ID

11759768

Incident

Aug 26, 2026

Transmission and transfer case failure. Noticed a very small amount of fluid leaking and took to dealership. Dealer informed me that I was "lucky" to have noticed and that the transfer case spline failure had occurred. Notified that the problem could lead to sudden loss of all wheel drive and loss of vehicle control, vehicle slipping, and oversteer. DP26001 had indicated that these issues are a safety concern and could lead to an accident. I had noticed instability in certain issues where the rear of the car did not feel firmly planted when cornering (oversteer). Dealer indicated that both the transmission and transfer case need to be replaced. I was ~8000 miles within powertrain warranty. Parts are on a national backorder which indicates a widespread issue. No warning lamps or indication of seal failure that leads to stripped splines off the shaft due to the fluid leak. NHTSA does not understand how the Acura SH-AWD system interacts with vehicle dynamics and handling, and loss of the rear wheel drive and its impact on oversteer would be absolutely NO DIFFERENT than a rear sway bar breaking under load while cornering. I experienced this exact symptom on [XXX] where the road goes from 3 lanes to 2 lanes on a sweeping right hand curve. This is where I had felt like I may lose control of the vehicle, the rear of the car started to come around and I had to steer into the slide to regain control of the vehicle. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11758705

Incident

Aug 14, 2026

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

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.