2020 Acura MDX: start-stop system problems

Filed Oct 15, 2026 · Engine · 70,357 miles · CA

The contact owns a 2020 Acura MDX. The contact stated that the vehicle was previously repaired under Technical Service Bulletins: 22-009, 22-024, and 23-002; however, the failure persisted following the repairs. The contact stated that while stopped at an intersection, the engine failed to restart after the Auto Start/Stop feature engaged, and the transmission independently shifted to Neutral (N). The contact shifted the transmission to Park (P) and pressed the Engine Start/Stop button to restart the vehicle. The vehicle was taken to the dealer, where it was determined that the starter required replacement. The dealer requested that the manufacturer replace the starter; however, the request was denied. The contact associated the failure with the federal safety agency Action Number: EA25004 (Engine and Engine Cooling). The failure mileage was 70,357.

Filed Nov 30, 2025 · TX

The Auto Start-Stop Technology is malfunctioning. I bought my 2020 Acura MDX in 2022 and with the first 2 weeks of having it, it turned completely off while in a drive through line. It only does this when the Auto start- stop is on. I took it back to the dealership and of course they found nothing wrong. This happens frequently and sometimes the car doesn’t want to start back up. Sounds like I am not the only one with the same issue.

Filed Jun 11, 2025 · Electrical, Engine · PA

I am writing to formally express my concern regarding a recurring issue with the Auto Start/Stop feature in my 2020 Acura MDX. This feature, which is intended to improve fuel efficiency, has instead caused unexpected and unsafe engine shutoffs while the vehicle is in operation. On multiple occasions, the vehicle has failed to restart promptly after the engine shuts off at a stoplight or in traffic, creating a serious safety hazard. The delay or failure to restart can leave the car temporarily disabled in active traffic, placing both myself and other drivers at risk.

Filed Apr 6, 2025 · Engine · CA

My Acura MDX 2020 had an issue in which the automatic start-stop system sometimes not manage to start the engine after stopping.

Filed Oct 22, 2024 · Electrical, Engine · MD

I came to a stop at a stop sign. The start/stop feature activated and the engine shut off. When I lifted my foot off the brake, the engine did not restart (as it's supposed to), and then vehicle automatically shifted itself into neutral (without any of my doing). I put the emergency flashers on to alert other motorists, hoping to avoid a rear-end collision as I was stopped in the middle of an intersection in rush hour traffic. At this time, the battery light illuminated. The engine light illluminated as well. I had to forcefully and unusually push the brakew pedal towards the floor as the vehicle was drifting backwards. At this time, the vehicle would not shift into park. Then "PARK" illuminated, so I attempted to reapply the brake hoping that when I let up from the brake the car would start again (like the usual procedure). The vehicle then shifted into park, but the engine had not restarted. I pressed the on/off red button to follow normal procedures for turning the vehicle off. With my foot remaining on the brake, I pressed the off/on red button to start the engine as usual and the engine finally restarted. Afraid for the safety for myself and other motorists, I put the vehicle into drive and I pushed the button to stop the stop/start system from engaging. No codes generated during this. This is a safety issue for several reasons. First, I was stuck in the middle of a busy intersection where a large volume of cars travel through each day. It was rush hour, so the roads couldn't be more filled. Someone coming around the corner who might not have been prepared to stop could have hit me. Likewise, I could have been hit while in the intersection. Secondly, once the vehicle failed to turn back on, the Washington Grove (Montgomery County Fire and Rescue Services - MCFRS) was responding to a vehicular file nearby on I-270 and had I not have been able to move in time, some of their vehicles likely wouldn't have made it through because my vehicle was blocking the lane.

Filed Jul 18, 2024 · Engine · VA

The car's Auto Start/Stop (AST) function is malfunctioning. It frequently fails to restart the engine after stopping, causing the engine to completely shut down at traffic signals. When this occurs, the car must be shifted to park and the engine manually restarted.

Filed Mar 26, 2024 · Fuel system, Transmission · MA

What component or system failed or malfunctioned, and is it available for inspection upon request? - Periodically After Auto Start Stop System activates (vehichle shuts down after stop). When the brake pedal is released and vehicle attempts to restart the engine stalls and is shifted into neutral. How was your safety or the safety of others put at risk? - UNK Has the problem been reproduced or confirmed by a dealer or independent service center? - No, this is an intermittent issue, this has occurred a few times (6). Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? - No, email sent to service department. Were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear? - Parking light, Brake system light, Oil pressure light, battery light.

Filed Nov 30, 2023 · Electrical · VA

While coming to a stop the engine start stop engaged causing the engine to turn off completely and would not restart when the throttle was pressed . The transmission shifted into neutral and the push button start would not fire the engine. Car would not go back to park. After locking and unlocking the door 30 seconds later it reset and the engine refired. This occurred with traffic flowing behind me and caused the car to be placed in neutral and the driver having no control over the vehicle. If this had occurred in an intersection while turning, the driver and occupants of the vehicle could be in significant danger of an accident. I took the car to the Acura dealer the next day and was told they had several complaints of this kind but would need to duplicate the issue on my car to assist me. If they could not duplicate the issue then the could not help me. At this time, it has not been inspected by the manufacturer. There were several warning lamps that came on when the car turned off.

Filed Nov 22, 2023 · Electrical · 31,500 miles · CA

The contact owns a 2020 Acura MDX. The contact stated while stopped at a stop light, the vehicle failed to restart, and the contact became aware the Auto START/STOP function was not operating properly. After manually restarting the vehicle, the vehicle returned to normal functionality, but the failure became a regular failure. No warning lights were illuminated. The vehicle was taken to the dealer, who was unable to duplicate the failure. The vehicle was not repaired. After investigating the failure, the contact related the failure to Technical Service Bulletin: 23-008. The manufacturer was not notified of the failure. The failure mileage was 31,500.