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.

Car engine went into idle mode while the Idle Stop was engaged while stopped on an expressway off ramp. Car engine did not turn back on and entire car shut down. It took about 1 minute to re-start the car and engine. Safety was compromised because car shut off in an unsafe location. No accidents or injuries occurred. This happened about a year ago and car battery and starter were replaced by the Acura Dealer November 2025. There were no warning lights or messages prior to this problem appearing. Prior to this event, car had been slow to turn over for about 1 week. I previously submitted a complaint to NHTSA in Fall 2025, case #11694662, when this happened the first time.

NHTSA ID

11765668

Incident

Sep 19, 2026

I own a 2025 Acura MDX A-Spec purchased in XXX from John Eagle Acura in [XXX]. The vehicle has less than 10,000 miles. Component/system: The Auto Idle Stop/start system has malfunctioned. During the past week, the engine unexpectedly shut off while stopped at red lights and stop signs approximately 4–5 times. When it was supposed to restart, the vehicle sometimes failed to restart normally and required multiple attempts. The vehicle and components are available for inspection upon request. Safety risk: These incidents occurred at intersections while I was stopped in traffic. When the engine failed to restart, I was unable to immediately proceed while vehicles were behind me, creating a potential collision and traffic hazard. I regularly have my two young children in the vehicle, making this especially concerning. Dealer inspection: I brought the vehicle to John Eagle Acura after experiencing the problem. The service advisor indicated that this is a known issue, and the vehicle was serviced for the concern. The failure occurred repeatedly in real-world driving, but I do not know whether the dealer was able to reproduce it during inspection. Manufacturer/other inspection: The vehicle was inspected by an authorized Acura dealership. It has not been inspected by police or insurance representatives. Warnings/symptoms: I received no prior notification or warning from Acura regarding this issue. The first incidents occurred during the week before my dealership visit. The engine shut off while stopped and then did not restart normally. I did not observe a warning lamp or message specifically indicating that the vehicle would fail to restart. After experiencing the problem, I learned that NHTSA has an ongoing investigation, EA25-004, involving Auto Idle Stop failures on Honda and Acura vehicles, including 2023–2025 Acura MDX models. I am submitting this complaint so these repeated incidents can be documented as part of NHTSA's review. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 5

NHTSA ID

11764853

Incident

Sep 16, 2026

The engine shut off at a red light via Auto-Stop and failed to restart, leaving the vehicle stranded in active rush hour traffic until a manual restart of the engine was performed. This issue has occurred multiple times now.

NHTSA ID

11764819

Incident

Sep 16, 2026

Auto Start/Stop At stop light car wouldn’t start after engaging Auto Start/Stop, had to turn on hazards, turn car off and restart with cars bearing down on me Monday 9/14, before entering traffic I stopped and Auto Start/Stop engaged but car wouldn’t start Got a jump and brought to dealership and they replaced starter motor

NHTSA ID

11764541

Incident

Sep 14, 2026

Battery keeps dying. Faulty starter leaving car stranded.

NHTSA ID

11763842

Incident

Sep 12, 2026

Auto start-stop system stalled my car at a red light few times. Also I can clearly tell starting/cranking it is lagging as well.

NHTSA ID

11763829

Incident

Sep 10, 2026

Car at a stop light, went into idle stop, and then shut off with an error message that to continue to drive, depress brake pedal and push switch. Car then needs to be restarted. This has happened 3 times in less than a week, so it is becoming concerning as a safety issue. The issue seems to be related to the starter and idle stop feature.

NHTSA ID

11763310

Incident

Sep 9, 2026

20 minutes after parking my car, it would not start. Several different codes came up on the gauges - BRAKE issue; hill issue;stabilization issue - multiple icons and warnings. I ended up having to be jumped off.

NHTSA ID

11763280

Incident

Sep 9, 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.

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.