2023 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.

splines between transmission and power take off unit(transfer case) striped and loss AWD function making vehicle FWD only

NHTSA ID

11774535

Incident

Oct 27, 2026

We purchased this 2023 Acura MDX less than a year ago and are under the 4 year 48,000 mile extended warranty, but also purchased warrantees to cover both the interior and exterior of the vehicle to have a worry-free experience for the entire life of the loan on the vehicle at the strong recommendation by the GM of the dealership. We had the vehicle serviced for an oil change on XXX and had no issues with the vehicle and nothing came up on their inspection while servicing. A week went by and we had a rain storm over the weekend and my wife noticed that the floor of the driver side was wet and then noticed the passenger side front was damp as well. She called the dealership to report it and brought the vehicle in right away to see what's going on. We were told that the cost of repair would be $3,450 to replace the rug and clear the drain house and make sure it no longer leaks. We were told they could clean and dry out the rug if wanted to go the least expensive route and would be about $2,000. We were told that because it was caused by external factors (rain and debris) that caused the drain hose to back up and cause water to leak into the car in multiple spots and would not be covered under ANY of the warrantees and would have to be paid out of pocket. After a bunch of discussions and back and forth we were told that we could submit it to our car insurance to help with some of the out of pocket coverage. We did not own the car last fall for enough debris to be in the drains, it is september weather (just officially fall) and only rained out as it does in [XXX]. We have other cars with sunroofs and neighbors with sunroofs with no problems. This repair should not be out of pocket and should be paid at the expense of Acura dealership and not by the owners who have spent thousands on fees, payments, warranty coverage, etc. We do not have the money to pay for this damage and now weeks have gone by with no resolve and are now also concerned with mold issues. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION AC

NHTSA ID

11771614

Incident

Oct 1, 2026

My vehicle developed a leak at the seal between the transfer case and transmission. I was informed that, due to the original design, this seal cannot be replaced independently. The leak can result in the loss of gear oil and transmission fluid, further transmission damage, and a loss of power to the rear wheels. Repairs involve significant expense, including replacement of damaged components, seals, and both fluids. There were no apparent warning signs other than oil puddles beneath the vehicle. Two extended warranty companies inspected the vehicle and denied coverage, stating that the manufacturer should be responsible for addressing the issue. The vehicle was taken to John Eagle Acura in Houston, Texas, for repairs involving replacement of the transmission and transfer case, along with all associated fluids and seals. I understand that this dealership has repaired other vehicles with the same issue and that similar cases have been reported nationwide. I am concerned that this may be a recurring design-related problem with potential safety implications, particularly because of the possible loss of power to the rear wheels without adequate warning. I request that the manufacturer investigate this issue, review these reported failures, and take responsibility for the necessary repairs.

NHTSA ID

11770530

Incident

Sep 4, 2026

These are OE tires on my 2023 Acura MDX. At 22,000 miles a rotating thumping sound was heard and also felt in the steering wheel. The tires were inspected by my Acura dealer on three separate service calls to diagnose. On the 3rd visit the problem was confirmed and determined to be severe flat spots on all 4 tires. Due to the flat spots, these tires are unbalanced and give off a vibration throughout the vehicle and steering wheel. The Acura dealer photographed the tires and filed a claim with Bridgestone. The claim was denied 11 weeks later. This unbalanced condition should be considered a safety issue, especially at high speed where a blow out is possible.

NHTSA ID

11768746

Incident

Dec 12, 2025

My 2023 Acura MDX has developed a windshield washer system failure affecting both the front and rear washers. The system is clogged and is no longer able to spray washer fluid properly. I found a documented case involving 2022-and-newer Acura MDX vehicles showing what appears to be the same failure mode: coating on the washer-fluid reservoir can become gel-like, enter the washer system, and clog the filter, pump, lines, and/or nozzles. Video reference: [XXX] The symptoms shown are essentially the same as those on my vehicle. I also found an American Honda service communication concerning the 2022 Acura MDX that specifically requested dealer feedback on vehicles with an inoperative or weak washer-fluid system and asked whether the washer tank and/or filter was clogged. This raises concern that the problem may be recurring across multiple model years and may be related to the washer-system design or materials rather than normal wear. I am submitting this complaint so NHTSA can evaluate whether this represents a broader safety-related defect affecting Acura MDX vehicles. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11768723

Incident

Oct 1, 2025

Was exiting I275 onto Westbound Route 32 when the brakes were unexpectedly applied by the vehicle’s safety system. No vehicles were in front or beside me. Very alarming when it happened. This also happed two other times at slower speeds.

NHTSA ID

11762170

Incident

Aug 18, 2026

2023 ACURA MDX TYPE S. 28k miles. While merging onto highway, I sped up and at 25 mph, I heard a loud metal clunk from underneath the car. Car still drove and functioned as a two wheel drive instead of AWD. Went in for service and was told that the transmission and Power train Unit would need to be replaced and will be replaced under powertrain warranty by Acura.

NHTSA ID

11758889

Incident

Aug 14, 2026

Was driving arround corner and felt a shudder like I had run over something, the felt front tires loosing traction and car jerked into next lane. Took to dealer and they diagnosed a failure of output shaft from transmission to awd transfer case, currently at dealer getting transmission awd assembly replaced.

NHTSA ID

11757047

Incident

Jun 25, 2026

Service Bulletin - Under certain circumstances, after coming to a stop and the idle stop feature engages, the vehicle may not automatically restart. In other circumstances, vehicles may experience a slow crank or fail to start under hot ambient temperature conditions.

Dealer Message - Under certain circumstances, after coming to a stop and the idle stop feature engages, the vehicle may not automatically restart. In other circumstances, vehicles may experience a slow crank or fail to start under hot ambient temperature conditions. The customer should be able to restart the vehicle by selecting Park and pushing the ENGINE START/STOP button.

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."

Dealer Message - American Honda Motor Co., Inc. (AHM) is searching for certain 2023-2025 MDXs with a client complaint of a no auto re-start condition after going into an auto idle stop. The push button ignition may or may not restart the engine. To better understand the cause of this condition, AHM would like to inspect the vehicle prior to you attempting a repair of any kind.

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.