2020 Acura MDX Electrical System Problems

During the summer of 2025, the auto idle engine railed to restart while at a stop light. We had to shut off and restart the car. We took it to the car dealer and they did some sort of software update. It happened again in January 2026 while at a stop light off a highway exit ramp. We took it to a different dealer because we were living in a different city at the time. In their computer system, they could see the repair that had been done. They did some sort of other update and submitted it as a warranty repair for Acura (which the other dealer had not done). They noted there was one other repair that could be done, but Acura would not allow them to do both at once and this update usually fixed it. However, it happened again in February 2026. The engine did not restart from auto idle, this time at a stop light toward the beginning of an eight hour road trip back home. Fortunately, turning off the engine and starting it back up worked. We took it back to the second dealer and they did the additional repair authorized by Acura and submitted as a warranty repair. Three incidents of the auto-idle not restarting the engine in less than a year is not acceptable. The car is unrealiable.

Intermitted Flashing Dash Lights, Headlights, and Car Alarms. Steering wheel moving up and down. Looks like the same issue as Service Bulleting 21-055.

Electric parking break and emissions light keep popping up. They says it’s the catalytic converter many people having the same issue

There was an active recall on this car from Acura for the auto start system malfunctioning. When the car auto stops at a signal or stop sign it does not turn back on sometimes. We took the car to Acura 3 times for the same issue and they keep saying that it is fixed but the recall was never fixed. This is highly dangerous in traffic situations when the car does not turn back on when you take your foot off the brake.

On Aug 8th at 3:32pm (81F and sunny), I stopped at a red light with the auto idle engine feature on. When I lifted my foot off the brake to drive the car, the car shifted into neutral and completely shut down and would not restart immediately. I attempted approximately 8 times to restart the car for 3 minutes before it successfully restarted. This poses a significant safety hazard for myself, my children, and others on the road. This is the 6th time this has happened and I have previously filed a NHTSA report # 11533671 with the same issue. Acura has been unable to diagnose and recreate the problem and is refusing to do any further work. It has been brought into their dealership on 3 separate occasions (July 2023, September 2024, August 2025). Prior to this occurring, there were no warning symbols, the car started fine without issue, and the battery has been checked and confirmed in working order.

I own a 2020 Acura MDX. On two separate occasions, the Auto Engine Idle Stop system failed to operate while depressing the accelerator pedal while at a stop. Several unknown warning lights were illuminated on the instrument panel. The vehicle shuts off and the I had to manually restart the vehicle after the failure. I have not contacted the dealer yet but based on what I have found here I am not the only one that this is happening too. It is awful to be stopped in rush hour traffic and having people honking at me and potentially be the cause of an accident. The vehicle has not been repaired. The failure mileage was approximately 35,000 and 38,000 miles.

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.

The contact owns a 2020 Acura MDX. The contact stated that on three separate occasions, the Auto Engine Idle Stop system failed to operate while depressing the accelerator pedal while at a stop. The contact stated that several unknown warning lights were illuminated on the instrument panel. The contact stated that the vehicle shut off and the contact had to manually restart the vehicle after the failure. The contact called and informed the dealer of the failure. The contact was then referred to the manufacturer for assistance with the repair. The contact was provided a case number and referred to the dealer to order the part for the repair. The contact made multiple attempts to reach the dealer but had not received a response. The vehicle was not repaired. The failure mileage was approximately 44,000.

1.17.25 My check engine light came on with the following lights: Emissions System Problem Electric Parking Brake Problem

The vehicle stalled and was unable to start again, Called AAA , they jump started but when I went to dealership they said it wasn't the battery. The car electrical electric system was flashing. The breaks won't release. This is not the first time. My car is currently in Acura service for 5 days and they can't figure out what the problem is. My friends car also has had similar issues. I have a video of the flashing indicators. The car has only 33k miles.

The contact owns a 2020 Acura MDX. The contact stated while coming to a complete stop, the vehicle started to stall. The contact stated that after the vehicle came to a stop, the vehicle would not turn on until after several seconds. There were no warning lights illuminated. The vehicle was stalling more frequently and was taking longer to restart. The vehicle was towed to an independent mechanic and was diagnosed with alternator failure. The independent mechanic could not find any other cause for the failure. The vehicle was repaired; however, the failure persisted. The local dealer was contacted; however, the vehicle was not repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 20,000.

My vehicle stalled and the engine cut while I was waiting at a stop light. The engine auto shut-off feature was active at the time of the incident. While sitting a the red light the auto engine feature shut the engine down, which is normal to reserve the use of fuel while at a stop light. When I took my foot off the brake, the vehicle should have restarted. but instead, the vehicle went into N (neutral) and the engine did not restart. I was sitting in the middle of traffic with cars behind me, so I put the emergency signal on, I then put it in P (park) and started the vehicle. This is the second time this has happened. The first time I thought I touched the neutral button by mistake. There were no injuries, but I'm concerned that this could cause a crash in the future,.

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.

When the vehicle is idle, for instance at a light, it will shut down. It idles a little, goes into neutral and shuts completely down having to be restarted. I always turn off the automatic start on the vehicle after I start it, so it is not that. It has also done it while driving. It is very unsafe to be driving in traffic and have your vehicle shut down with no warning. Please advise on what actions should be taken to correct this issue.

When using the a/c while the Auto Idle Stop is engaged, the engine will shut off and not restart. This issue does not happen immediately, at the first cycle of being activated, it's after 3 or more cycles of the AIS being in use, like driving in stop and go traffic for instance. The issue reminds me of a low/dying battery when it happens. Now when I turn off the A/C, the car starts right up like normal. Also if I don't use the A/C, the AIS cycles like normal, like in traffic, l'll have no problems with its performance.

Twice so far my car just turned itself off while stopped in traffic at a stoplight. It would not turn on immediately. Traffic built behind me, steering was locked, brakes not working. After sitting a minute or so it would start again and then the steering would then work, gas accelerator, brakes would all then start to work again. It was scary and unsafe. This needs a recall!!!

I've experienced stop and stall issues with my vehicle three times and the Acura dealership said they couldn't locate but kept my vehicle for a few days and said it was the battery. I have a new battery but same issue occurred two more times. There is definitely an electrical problem with this vehicle's system. The radio randomly stops working, no sound or buttons stop at any given time and also heat/air buttons switch by themselves. Shift paddles sometimes does not slow down vehicle, in most cases it accelerates.

I was on a bridge heading into a tunnel stopped due to traffic and the car shut off completely. The screen said to put the car in park and restart it. I tried several times and after a few attempts it started back up. This is the third time this happened. I had a recall when I purchased it and had the recall addressed for the same issue. Now I am back at Acura again. And being told I may have to pay for diagnostics. The car is still under warranty.

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.

Auto braking system engaged abruptly, without necessity. This occurred twice (December 2022 and November 2023) almost causing collisions on both occasions. The dealer could not reproduce the problem when it was brought in in December 2022 and said this could occur if the sensors are dirty and to ensure they are always clean. I have since done so, and the same thing happened again. There were no warning signs for this error prior to it occuring.