2025 Acura MDX Engine Problems

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

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

Four times in 18 months, with the most recent happening last month and today, I was at a stoplight and turned my manual idle off. The light changed and the car would not move despite me stepping on the gas. It told me to restart the car which I did but the first attempt didn’t work to restart. After a few minutes I tried restarting again and it struggled but did. I was very worried as there was a car behind me who thought we were moving with the green light and fortunately he moved to the other lane to avoid a collision as it took me a minute to figure out the car had stopped before putting in my hazards.

NHTSA ID

11751202

Incident

Jul 17, 2026

I had driven 1.5 hours of highway driving. Exited highway and at the first stop light the car stalled on a busy four lane road. I have had the recall software update. Took a minute or 2 to get the car restarted

NHTSA ID

11749909

Incident

Jul 12, 2026

I was stopped at a red stop light waiting to turn left when my 2025 Acura MDX engine auto-stopped per the auto-stop feature. When the light turned green, I removed my foot from the brake and pressed the gas. The engine did not auto-start and displayed a message on the dash telling me to depress the brake and press the ignition button to continue driving. I did this several times, each time the dash would go black for a few seconds then come back up with the same message. Eventually, after getting the car to completely turn off, waiting 30 seconds, and restarting it, I was able to get the engine to start. While all of this was happening, I was passed unsafely by several angry drivers who were behind me, including one who tried to cut around me after I was able to get the car restarted, nearly clipping the front-right corner of my vehicle. I have an appointment with the dealer to have the issue investigated, but the appointment is not for another week. There was no indication of trouble prior to the first time this occurred. We have had this issue at least three times in the past week.

NHTSA ID

11748754

Incident

Jul 6, 2026

On June 9, 2026, my 2025 Acura MDX, with only 9,139 miles, stalled at a red traffic light after the Auto Idle Stop feature activated. The engine would not restart, leaving the vehicle disabled in an active traffic lane. I was unable to shift the vehicle out of Park and was stranded for approximately 5 to 10 minutes with my two young children in the back seat. The dashboard instructed me to fully depress the brake pedal and press the ENGINE START/STOP button to restart the vehicle, but repeatedly following those instructions did not restart the engine. There were no warning lights or other symptoms before the incident. I feared another vehicle would rear-end us because I could not move the vehicle out of the travel lane. After multiple attempts to turn the vehicle off and back on, it eventually restarted, allowing me to drive home. The vehicle was towed to the Acura dealership on June 10, 2026. The dealership inspected the vehicle, diagnosed a failed starter, and told me the failure was caused by the Auto Idle Stop feature. The starter was replaced, and I was instructed to disable the Auto Idle Stop feature every time I start the vehicle to help prevent the problem from happening again. The dealership has records of the repair, and the vehicle is available for inspection upon request.

NHTSA ID

11747615

Incident

Jun 9, 2026

The contact owns a 2025 Acura MDX. The contact stated that while stopped at a red light, the vehicle suddenly lost automotive power. The message, "Transmission System Failure - Apply Parking Brake while Parked - See Dealer," was displayed. The gear shifter indicator warning light was occasionally illuminated. The contact stated that while attempting to use the Push-To-Start feature to start the vehicle, the engine hesitated while turning over. The vehicle was taken to a local dealer and was diagnosed with starter failure. The vehicle was repaired under warranty. The manufacturer was not made aware of the failure. The failure mileage was approximately 10,000.

NHTSA ID

11747338

Incident

Sep 15, 2025

Mileage

10,000 mi

No restart after auto idle stop - Car fails to restart automatically after stop and releasing the brake pedal. This has happened on a number of occasions in the last few months.This can cause a dangerous condition that can can cause an accident if stopped in an intersection or a rear end collision as the driver behind assumes the vehicle will move but does not. Car has to be shut off to restart.

NHTSA ID

11747083

Incident

Jun 28, 2026

2025 Acura MDX will turn off with the auto on/off feature at red light but has had issue several times with turning back on. The car turns completely off and have to push start button to turn back on. On one occasion the same issue happened but would not immediately start with the push start again.

NHTSA ID

11746622

Incident

Jun 23, 2026

Randomly when auto/start stop feature engages and shuts down the engine when I let go off the brake the engine doesn't restart and a system problem message show up on the dash. Have to shut down the car and restart for the engine to start running again.

NHTSA ID

11745473

Incident

May 28, 2026

My Vehicle is having an issue with the idle stop feature. Multiple times when stopped at a red light or when idle the car stops and will not turn back on. I have to turn the car off completely open the door to simulate leaving the car, wait a minute then start the car again to be able to move.

NHTSA ID

11739504

Incident

May 8, 2026

the car shuts off at a red light, fails to auto-restart, forces the car into Park, and requires a full manual reboot or jumpstart while stuck in moving traffic. It also struggles to turn on at times mimicking a drained battery. I am needing to deactivate the auto start/stop feature in order for the vehicle to properly function. Vehicle will not start when parked at times.

NHTSA ID

11739107

Incident

Jan 17, 2026

Description of Incident: While stopped at a red light at a busy intersection near a shopping district, the vehicle's Auto Idle Stop (AIS) system engaged and shut off the engine. When I attempted to restart by pressing the brake pedal — as instructed — the vehicle failed to restart. The dashboard displayed an error message reading "Idle Stop Function: Press Brake to Restart." My foot was on the brake pedal at the time; pressing it did not restart the engine. I then manually shut off the vehicle using the Engine Start/Stop button and attempted to restart it. The vehicle would not start. I remained stranded at the intersection for approximately 10 minutes. I had to call the cops for a patrol car because other cars were piling up behind me and I had my 6 month old son in the vehicle. Safety Impact: During this time, I was unable to move the vehicle from a live traffic intersection. This created an immediate safety hazard to myself, my family, and other drivers.

NHTSA ID

11738536

Incident

May 18, 2026

While stopped at a red light at a busy intersection near an airport, the vehicle's Auto Idle Stop (AIS) system engaged and shut off the engine. When I attempted to restart by pressing the brake pedal — as instructed — the vehicle failed to restart. The dashboard displayed an error message reading "Idle Stop Function: Press Brake to Restart." My foot was on the brake pedal at the time; pressing it did not restart the engine. I then manually shut off the vehicle using the Engine Start/Stop button and attempted to restart it. The vehicle would not start. I remained stranded at the intersection for approximately 10 minutes before the vehicle finally restarted and allowed me to shift into Drive. I was the first car in the lane, so people kept piling up and honking behind me.

NHTSA ID

11738526

Incident

May 7, 2026

The auto idle stop feature will kick in at red lights, shutting the engine down. However, every approximate 1 out of 10 times the engine and electrical system fully shut down when I try to start the car moving again. The car can then not be restarted for close to a minute. This results in not being able to move when the light turns green and is dangerous is heavy traffic areas.

NHTSA ID

11737684

Incident

Mar 1, 2026

Car engine turns off at a red light, by turn off I mean completely turned off, not just silent. And takes a couple of attempts to restart the car before the engine turns on again. This has happened over 5 or 6 times over the last 3 months, however yesterday (May 9, 2026) it happened twice within the hour. Luckily, I have not been involved in an accident because of this, but I'm concerned that it's easy to imagine a scenario where someone will be rear-ended. Please issue a safety recall for Acura to fix this issue.

NHTSA ID

11736850

Incident

May 9, 2026

Last year, my 2025 Acura MDX was repaired under warranty for a known starter issue that is affecting all 2025+ MDX models. The issue is that the vehicle will stall or fail to start on random occasions leaving drivers stranded or stopped in traffic unable to move their vehicle. Honda and Acura are well aware of the fact that this is an issue, yet they continue to produce these vehicles with the same parts. This repair took several attempts and the dealership refused to even diagnose the issue for several months causing me to have to record each instance on my phone for proof. Once they eventually replaced the starter, the issue went away for approximately 10 months. Today, however, I was temporarily left stranded at a gas pump as my vehicle would not start. Honda and Acura dealerships are replacing these parts with the exact same part number, so the no-start condition comes back in about a year or less. It is incredibly dangerous to have a vehicle that you cannot move as anticipated, or if you’re in an area that you cannot leave or get away from potential danger because your vehicle won’t start. This is a less-than two-year-old vehicle that has now left me stranded on several occasions including in the middle of traffic on a motorway. I know for a fact that several other owners of the Acura MDX are having the exact same issue and ask that you please launch an investigation into this as Honda is well aware of it and still refuses to address the blatant safety risk it poses to its customers.

NHTSA ID

11735656

Incident

May 4, 2026

Engine stalls when at intersection and the engine cuts off at idle and fails to start back up when you remove your foot from the break. Can have keep lane assist enable. KLAS mode narrow, you have to fight the wheel to maintain control of the vehicle, formal mode is a 50/50 chance it works, wide you can sift right off the road for 5-10 secs before to realize your off the road. Steer wheel control button intermittently fail and stop being able to control the midi instrument panel and infotainment system. I believe there is a systematic electrical issue in the car. They attempted to fix this by replacing a starter which hasn’t because the engine stalled at an intersection again and on cold start this morning 5/4 at the same intersection as this is by my girlfriends apartment.

NHTSA ID

11735602

Incident

Apr 29, 2026

While stopped at a traffic light, the vehicle had auto shut off normally. However when I released the brake and pushed the gas it unexpectedly stalled and shut off without warning. When attempting to restart the vehicle, it would not start again. There were no prior warning indicators or messages suggesting an imminent issue. This created a hazardous situation as the vehicle was disabled in an active traffic lane. After several attempts, the vehicle either restarted after having set the emergency brake. The failure appears to be sudden and without driver input, raising concerns about reliability and safety in traffic conditions.

NHTSA ID

11735584

Incident

May 4, 2026

Vehicle is equipped with start stop system and we have had multiple instances where we come to a stop , and the car will not restart. In the latest instance, we pulled up to stoplight, the start stops system engaged shutting off the engine then wouldn't restart. Car also wouldn't turn completely off, so I had to hit the flashers at the busy intersection, try to get the car into park, then shut completely down, then restart the car. It also struggled to restart as if the battery was dying. In this instance most dash lights come on, but it appears to be an engine, electrical, and software issue. The vehicle has been inspected by the dealer multiple times, and in once instance they said the issue was caused by a bad battery, mind you the car is slightly over a year old. This latest time, they claimed that the battery was good and no issues were found. This issue continues to put me and my family at risk by leaving us disabled in the middle of traffic especially when it has happened near exiting the freeway,

NHTSA ID

11735372

Incident

May 2, 2026

I am reporting a serious safety defect involving repeated engine stalling and failure to restart associated with the auto idle stop/start system on a 2025 Acura MDX. The vehicle was leased in December 2024. Beginning in late summer and early fall of 2025, the vehicle intermittently shut off at stops and failed to restart when releasing the brake. This resulted in the vehicle becoming unresponsive in active traffic conditions, creating a significant safety hazard. The vehicle was presented to an authorized dealer for this issue on multiple occasions: August 15, 2025 September 9, 2025 October 31, 2025 After repeated unsuccessful attempts to diagnose and repair the condition, the dealer ultimately replaced the starter on October 31, 2025. This repair did not permanently resolve the issue. In April 2026, the vehicle again began exhibiting hesitation and delayed engine restart following auto idle stop events. On April 30, 2026, the vehicle stalled again, demonstrating that the defect persists despite prior repair efforts. This condition is intermittent and unpredictable, which increases the risk, as the vehicle may fail to restart when entering or crossing intersections or when moving with traffic. The inability of the vehicle to reliably restart creates a clear safety concern. Given the repeated repair attempts and recurrence of the defect, this appears to be a systemic issue rather than an isolated component failure.

NHTSA ID

11735131

Incident

Apr 30, 2026