2022 Acura MDX

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.

While driving at approximately 35 mph on a surface street with my wife and five-year-old son in the vehicle, the electric power steering system failed and steering assist was reduced. The instrument panel simultaneously displayed and cycled through multiple warnings including "Electric Power Steering System Problem — Steering Assist Reduced," "Brake System — Brake Hold System Problem," Vehicle Stability Assist, and Hill Start Assist. There were no warning lamps, messages, or symptoms of any kind prior to this failure; the first indication was the failure itself while the vehicle was in motion. On the two engine starts following the incident, the same dashboard warnings reappeared, although power steering and vehicle operation seemed normal. On the two starts after that, the vehicle started with no warnings and no indication of any problem. So the steering effort increased during the initial failure and I was unable to rely on power assist while moving in traffic, which created a risk of loss of directional control and a crash for my occupants and other road users. On Aug 11,2026, the vehicle was taken to an authorized Acura dealer, which confirmed a stored diagnostic trouble code and diagnosed a failure of the VSA (Vehicle Stability Assist) modulator-control unit, recommending replacement. The vehicle has not been inspected by the manufacturer, police, or an insurance representative. No repairs have been performed to date and the vehicle and component remain available for inspection upon request. Mileage at the time of failure was 40,090. I have video of the instrument panel recorded during the event and it is available upon request. I have reviewed complaints filed with NHTSA describing what appears to be the same simultaneous multi-system failure on 2022 and 2023 Acura MDX vehicles.

NHTSA ID

11756386

Incident

Aug 10, 2026

The contact owns a 2022 Acura MDX. The contact stated that while driving at an undisclosed speed, there was an abnormally rough grinding sound coming from the vehicle. There was no warning light illuminated. The vehicle was towed to a dealer, but the failure was not duplicated. The vehicle operated normally for a while. The vehicle was taken back to the dealer to be diagnosed. The dealer determined that there was a failure within the transfer case, causing the vehicle to be operable only in Front Wheel Drive. Additionally, there was debris inside the transmission. The vehicle was repaired out of pocket. The manufacturer was notified of the failure. The failure mileage was 80,000.

NHTSA ID

11756323

Incident

Apr 1, 2025

Mileage

80,000 mi

The contact owns a 2022 Acura MDX. The contact stated that drops of fluid were discovered on the floor of the garage. The contact stated that while driving at an undisclosed speed, the vehicle failed to properly accelerate while depressing the accelerator pedal. The vehicle was taken to the local dealer for diagnosis, and the contact was informed that transmission fluid was leaking due to a failure of the Power Take Off (PTO) unit and transmission spline, causing the transmission to overheat and leak fluid. The contact was informed that the transmission and PTO unit needed to be replaced. The vehicle was not yet repaired. The manufacturer was not notified of the failure. The failure mileage was 97,000.

NHTSA ID

11755172

Incident

Jul 1, 2026

Mileage

97,000 mi

The contact owns a 2022 Acura MDX. The contact stated that while the vehicle was receiving a routine oil change, the rear wheels failed to rotate. No warning lights were illuminated. The vehicle was taken to a dealer where it was diagnosed and determined that the transmission and transfer case needed to be replaced. The contact stated that the drive shaft was moving freely while in park. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was approximately 134,984.

NHTSA ID

11753972

Incident

Jul 2, 2026

Mileage

134,984 mi

Took car in for oil change and service tech saw that there was transmission fluid leaking. They then found that the splines were sheared off going into the transfer case and transmission. We received new transmission and transfer case. So far everything is working. We did not get any warning that there was an issue until we took it to the dealership. Putting in the case as this seems to be a common issue on type s models.

NHTSA ID

11753342

Incident

Jul 17, 2026

Vehicle exhibited a fluid leak at the rear of the engine near the transmission/transfer case junction. An independent shop is currently evaluating; suspected power take-off unit failure. This matches the failure pattern described in NHTSA Defect Petition DP26001 covering 2022-2023 Acura MDX and 2021-2023 Acura TLX for interfacing spline failure between the transmission and the rear-wheel-drive power take-off unit. Separately, while pulling out into traffic, the vehicle hesitated and failed to accelerate as commanded, chugging briefly before delivering power. This nearly resulted in a collision. No warning lamps or messages appeared at any time. Whether this drivability event and the fluid leak share a cause is UNKNOWN, but I am reporting both given the open defect petition on this component. Vehicle at approximately 75,000 miles, outside powertrain warranty by roughly 5,000 miles. Manufacturer declined assistance when contacted. Component is available for inspection upon request. Sudden loss of all-wheel drive without warning is a safety concern in Michigan winter driving conditions Repair has been quoted at approximately $3,600 for the transfer unit alone, plus labor, with no manufacturer assistance offered.

NHTSA ID

11753157

Incident

Jun 1, 2026

The Super Handling All-Wheel Drive (SH-AWD) system unexpectedly deactivates during cold weather conditions, creating a sudden loss of traction and compromising vehicle stability control on winter roads."

NHTSA ID

11752296

Incident

Jan 10, 2026

The splines to the transmission and front transfer case are worn and stripped and that is causing a bad transmission fluid leak. The fix for this unfortunately is to replace the Transmission and the Transfer case assy. I am not getting any support from Acura, as this is a known problem according to the dealer. Acura is not cooperating and the cost to repair is $14,000. I noticed a transmission fluid leak, so I took the vehicle into the Acura dealership. No check engine light came on, no notification that there was a catastrophic failure occurring to my car. I've been reading that this is happening to several other Acura vehicles as well.

NHTSA ID

11752070

Incident

Jul 18, 2026

Tech Line Summary Article - Customers are complaining of a clicking noise from front of vehicle while turning at low speeds. This is a temporary solution to address the issue.

"Service Bulletin - A pop noise can occur from the rear roof area when turning into driveways, bumps, or on an incline due to, in some cases, the panoramic roof frame mounting bolts are unable to maintain the necessary clamp force. This can allow shifting, which may lead to a pop noise."

Tech Line Summary - Customers are complaining of a clicking noise from front of vehicle while turning at low speeds. This is a temporary solution to address the issue.

Service Bulletin - Customers are experiencing screeching, squeaking, rubbing, or scraping from the rear wheel area due to rocks are getting caught between the rear brake disk and splash guard.

Dealer Message - American Honda Motor Co., Inc. (AHM) is searching for certain 2019-2025 RDXs and 2022-2025 MDXs with a client complaint of a pop noise in the rear sunroof area. Clients may describe a single pop noise heard while driving over a bump or turning in and out of driveways. To better understand the cause of this condition, AHM would like to inspect the vehicle prior to you attempting a repair of any kind.

Dealer Message - American Honda Motor Co., Inc. (AHM) is searching for certain 2019-2025 RDXs and 2022-2025 MDXs with a client complaint of a pop noise in the rear sunroof area. Clients may describe a single pop noise heard while driving over a bump or turning in and out of driveways. To better understand the cause of this condition, AHM would like to inspect the vehicle prior to you attempting a repair of any kind.