2025 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.

I am reporting a safety issue with my 2025 Acura MDX involving the Auto Idle Stop/Start system. When the vehicle comes to a stop and the Auto Idle Stop system shuts the engine off, the engine does not always restart as it is supposed to. When this occurs, pressing the START/STOP button does not immediately restart the vehicle. This has left me unable to move the vehicle normally after the engine shuts off and creates a serious safety concern, particularly when stopped in traffic or at an intersection. I have reported this problem to my Acura dealership numerous times. I have been told that Acura is aware of the issue but has not developed a solution. Despite my repeated complaints, the problem remains unresolved. My vehicle currently has approximately 22,000 miles. I am concerned that the vehicle may fail to restart after Auto Idle Stop activates and leave me stranded in an active traffic lane or intersection, creating a risk of a collision. I am requesting that NHTSA document and investigate this safety issue involving the 2025 Acura MDX.

NHTSA ID

11756581

Incident

Apr 14, 2025

My vehicle was stopped at a busy intersection, idling in the automatic stop mode. When my husband moved his foot from the brake to the accelerator, the car stalled, orange alarm alerts went off, and the car was completely dead and stalled without power. The car needed to be restarted, and it took a few attempts to accomplish that task. I have had the same problem before with this car and have had it into the dealer at least two times without resolution.

NHTSA ID

11756035

Incident

Aug 10, 2026

Auto Idle Restart failed three times in traffic at red light. Have to shift to Park and push Start button. Nothing happens for several seconds, then engine starts.

NHTSA ID

11755686

Incident

Aug 8, 2026

The contact owns a 2025 Acura MDX. The contact stated that while at a complete stop at a traffic light, the vehicle unexpectedly shut off and failed to restart. After approximately 15 minutes, the vehicle restarted, and the contact drove into a parking lot before driving to the residence. No warning lights illuminated. The dealer was notified of the failure the following day, and a service appointment was scheduled. The vehicle was not diagnosed or repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 14,000.

NHTSA ID

11755315

Incident

Aug 5, 2026

Mileage

14,000 mi

While at a stop light, the vehicle had automatic start/stop on and failed to restart when the gas pedal was applied. The car went into park but still seemed like it was on, even though it was not. I had to remain calm, put on my hazards, and attempt a couple of times to reboot the vehicle. This has happened at least three times since I purchased my 2025 Acura MDX in November 2025.

NHTSA ID

11754284

Incident

Jul 31, 2026

I am writing to formally report a serious and recurring safety defect with my 2025 Acura MDX A-Spec (VIN [XXX]) involving the Auto Idle Stop system. The engine repeatedly fails to restart after the Auto Idle Stop feature shuts it off. When my wife releases the brake pedal (for example, at a traffic light), the vehicle either stalls completely or experiences a major delay before restarting sometimes lasting more than 20 seconds, leaving the my wife unable to accelerate. This creates an immediate and unacceptable safety hazard, particularly in intersections or heavy traffic. I previously brought the vehicle to Acura of Langley regarding this exact issue. Despite that visit, the problem has continued. Most recently, on today, while my wife was driving with my kids, the vehicle again entered Auto Idle Stop at a traffic light. When the light turned green, the engine completely shut off and would not restart for more than 20 seconds. This left her stranded in traffic and unable to move the vehicle, creating a clear risk of collision. This is not an isolated complaint. The National Highway Traffic Safety Administration (NHTSA) has opened Engineering Analysis EA25004 into precisely this condition “No Restart After Auto Start/Stop Engages” affecting, among other models, 2016–2025 Acura MDX vehicles. American Honda has also issued dealer communications specifically seeking 2023–2025 MDX vehicles with client complaints of no auto re-start after Auto Idle Stop for inspection prior to any repair attempts. Class-action investigations and prior litigation involving related Idle Stop failures further underscore the known nature and seriousness of this defect. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11754100

Incident

Jul 31, 2026

I am submitting this complaint regarding my **2025 Acura MDX**, which I currently lease. The vehicle has an ongoing starting system malfunction that has not been resolved despite multiple service visits. I believe this issue presents a significant safety risk. The primary issue involves the **Auto Idle Stop/Auto Start-Stop system**. When the vehicle automatically shuts off at a red light, stop sign, or while idling, it will occasionally fail to restart when I release the brake or attempt to accelerate. Instead of restarting normally, the vehicle hesitates, stutters, or remains off. This creates a dangerous situation because the vehicle is unexpectedly disabled while in traffic, increasing the risk of being rear-ended or causing an accident. In addition to the Auto Idle Stop issue, the vehicle also has problems during the initial startup. When I attempt to start the vehicle using the push-button ignition, it frequently fails to start on the first attempt. I often have to press the start button a second time before the engine starts, and even then, the engine stutters or hesitates before finally turning over. This should not occur in a brand-new 2025 vehicle. I have taken the vehicle to the dealership multiple times for this issue: * During the first visit, I was told the battery was the cause. * During the second visit, the starter was replaced. * After the problem continued, I returned again. The dealership tested both the battery and the replacement starter and advised that both components were operating properly. * The dealership then opened a case with Honda/Acura engineering for further investigation. Despite these repeated repair attempts, the issue remains unresolved. I have been told that it is likely a software issue and that engineers are "looking into it." In the meantime, I was instructed to simply disable the Auto Idle Stop feature every time I start the vehicle. This is not an acceptable solution. I do have videos but it will now allow me to up

NHTSA ID

11754009

Incident

Jul 30, 2026

The vehicle developed repeated front‑end structural and steering problems shortly after purchase. During normal driving, it produced loud popping, creaking, and clunking noises when turning, entering driveways, or driving over small inclines. Steering felt inconsistent and the front suspension felt unstable. These symptoms created a serious risk of loss of control. A dealer confirmed the problem multiple times and replaced several major components, including the left front strut, the left front lower control arm, and the front shock absorber fork. The most serious finding was cracked welds in the front subframe, requiring the entire subframe to be replaced. A cracked subframe weld is a structural failure that can affect steering stability and crashworthiness. The issues were reproduced and documented by the dealer on multiple visits. The manufacturer’s engineering team was involved due to the severity and difficulty of diagnosis. Despite repeated repairs and extended time out of service, the same steering and suspension symptoms continued, and the vehicle was returned multiple times with ongoing issues. There were no warning lights or messages before the failures. The defects occurred during low‑speed maneuvering and normal driving conditions. The vehicle did not perform like a safe, structurally sound new vehicle, and the repeated structural and steering failures pose a safety risk to occupants and others on the road.

NHTSA ID

11751959

Incident

Oct 15, 2025

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.

Dealer Message - American Honda Motor Co., Inc. (AHM) is searching for certain 2024-2026 MDXs with a client complaint of the Malfunction Indicator Light (MIL) on with the DTC P0441 (EVAP System Purge Flow Malfunction) stored. 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 2024-2026 MDXs with a client complaint of the Malfunction Indicator Light (MIL) on with the DTC P0441 (EVAP System Purge Flow Malfunction) stored. 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 2024-2026 MDXs with a client complaint of the Malfunction Indicator Light (MIL) on with the DTC P0441 (EVAP System Purge Flow Malfunction) stored. 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.

Tech Line Summary - The vehicle's infotainment system displays previously viewed SMS messages upon each ignition cycle, when the customer's Android phone is connected via Bluetooth.

Over The Air System Updates - Vehicles equipped with the System Updates application are capable of downloading and installing Over the Air System updates (OTA). A connection to a Wi-Fi network is needed to perform the update over the air. System updates contain upgrades that fix operational errors and/or provide a variety of enhancements, which adds new functionality. Information about the various software releases can be found in this document.