2020 ACURA MDX Engine Problems

Car started to accelerate randomly and 2 seperate occasions while driving, Car started to decelerate / Brake randomly while driving

On December 4th I noticed a rattling sound when I was driving. It worsened when my car would rev above 2RPMs and before shifting. It also would make a terrible grinding sound when I started the car. I had about 1/4 of a tank of gas and thought that maybe that was part of the issue. After filling up, the sound was not as loud, but was still present when I started the car and upon accelerating. I took my car to my Acura dealership on December 5th. Within an hour of having the car they called to tell me that the engine needed to be replaced due to a connecting rod failure. They told me that the car is no longer safe to drive and that the repairs would be required in order to continue to use the vehicle safely. There was no warning sign. My only other concern...

I was at a red light with the idle stop automatically triggered. When the light turned green, and I pressed the accelerate pedal, the car would not move. I looked and saw the car had shifted itself to N (neutral) when it should have stayed at D (drive). I pressed the "D" button to drive but it stayed in N. There was a green light around the N button indicating the selected button. I had to turn off the car, turn on the car two times before the car recognized I wanted to press the "D" button. The screen by the steering wheel had some sort of message but I don't recall what it said. The word "accessory" might have been part of the message. This is absolutely a safety risk for myself and others. I had cars behind me at the green light honking. I had to turn on...

There was a couple times where the car stalled at a red light. Also, there are a lot of times when I press the push to start, it will not start, advising me to place the key fob near the push to start. I find this to be dangerous when driving and very annoying when attempting to start and it doesn't start.

My 2020 model Acura MDX is experiencing unexpected engine shutdowns while braking during motion. The issue has been reported multiple times to the vehicle manufacturer and their authorized dealers; however, their responses have been consistently unhelpful and have not resolved the problem. I currently have an open complaint with American Honda Motor Co., Inc. since December 2023 Case Number: 14329512 Additionally, I have found numerous reports online from other owners of the same model experiencing the same issue, as documented here: 🔗 2020 Acura MDX Engine Complaints – CarComplaints.com This recurring malfunction presents a serious safety risk, especially in moderate traffic conditions, where sudden engine failure during braking could lead to collisions or injuries.

I was driving on the interstate when suddenly the check engine light began to flash and the car lost power. I was traveling at 70 mph and the sudden loss of power caused the vehicles behind me to move into the other lane to prevent rear ending me. While there was no accident, there could have been if the other drivers were not reactive. There was no advanced warning. This could have been deadly for me and my family. I was several miles from home and needed to have the vehicle towed to a mechanic who stated it sounded like a rod bearing and suggested we take it to an Acura dealer. We are yet to have a resolution.

At a red light or stop sign, my MDX switches into Neutral without me knowing it. When I press the gas to go, my car won't move. Other vehicles behind me almost hit me as they expect me to go. I can't switch into drive. I must turn off car and then turn it back on. I feel this is very dangerous. This happens about once a week now. The MDX was just in for service and recalls a few months ago. Nothing was noted about the engine on the reports.

When the vehicle stops and the idle auto-start/ stop engages, the vehicle will automatically go into neutral and cannot be restarted until the vehicle is turned off then back on. This has happened at both stop lights and on the highway and almost caused a very serious rear end accident.

The contact owns a 2020 Acura MDX. The contact stated that occasionally, while driving at various speeds, the vehicle stalled. There was no warning light illuminated. Additionally, while the vehicle was stopped at a traffic light, the Auto Idle START/STOP failed to operate as designed, and the vehicle failed to restart. The vehicle was taken to a local dealer; however, the cause of the failure was unknown. Upon further investigation, the contact related the failure to an unknown recall; however, the VIN was not included. The manufacturer was made aware of the failure. The failure mileage was approximately 10,000.

The idle stop feature does not work correctly. A couple times the car did not restart while stopped at a red light. Had to put into park and took about a minute to restart.

I own a 2020 Acura MDX. The Auto Engine Idle Stop system failed to operate while depressing the accelerator pedal while at a stoplight. The vehicle shifted automatically to neutral and would not let me switch to drive. I just recently purchased this car (less than two weeks). Based on what i see online and all the complaints on here , this is a known issue. However when i contacted my local Acura they acted as if they never heard of this issue and they want to diagnose my car at my expense. The mileage on my vehicle is between 31,000 and 32,000. I purchased this vehicle to accommodate my newborn granddaughter. Now, I don't feel like its the safe vehicle its advertised to be. This is a very dangerous thing that is happening, how many complaints need to be submitted before the manufacturer is held accountable.

1. The car accelerates by intself. The accelaration is like "hiccups". When reversing and changing to D gear, it takes longer than usual for the accelarion to take effect. Yes, car is available for inspections 2. It is dangerus because it gets the hiccups even at high speeds. If it is a serious egine problem, which seems like it is, could cause an accident. 3. The car was taken to the dealership for 3 recalls but it got worse after the recalls were fixed. Supposedly the recalls were supposed to fix the issues. We have not taken it back yet. 4. There is no lights or warnings when it does it.

The contact owns a 2020 Acura MDX. The contact stated that on several occasions, while coming to a stoplight, the vehicle lost motive power. There was no warning light illuminated. The vehicle was able to restart. The vehicle was taken to the dealer; however, the vehicle was not diagnosed or repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 46,000.

connecting rod bearing failure confirmed by independent mechanic. No alerts or warning lights. Problem just showed up and engine started knocking on acceleration.

On multiple occasions when the car is stopped at a light, in traffic or at a stop sign and the auto idle stop feature is engaged the car will shut off and not restart for up to 1 minute. We have always been able to get it to restart but feel it is dangerous to be stopped so long in moving traffic.

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,...

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.

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.

When idle stop is on and I come to a stop, the car shuts off and switches to neutral. It has to be put in park to start it back up. This is a safety concern because the vehicle is essentially stalled until you're able to put it in parked and restart it, which could cause an accident. The dealer is aware of the problem as it's been discussed the last two times that I've taken my vehicle in for recalls. According to the dealer, there is a recall for this issue but it's not for 2020 MDX, it's for 2022-2025.

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.

Auto Idle Stop issue where engine did not restart. Occurred multiple times in April/May of 2024 and Vehicle Stability Assist Code U3006-16 appeared on the Infotainment screen. Taken to dealer who was unable to replicate the problem. The U3006-16 code appeared again in February 2025 but the car did not experience the restart issue at that time. The U3006-16 code appeared again on April 6, 2025 while exiting a freeway after a 20 minute drive and the engine did not restart after Auto Idle Stop engaged at the second intersection. Taken to dealer and unable to replicate the problem and supposedly cleared the codes. On May 21, 2025 the U3006-16 code appeared again while exiting a freeway after a one hour drive but the car did not experience the restart issue at that time. Took car to dealer who checked a bunch of things and cleared the code,

At 101,841 miles, noticed ticking coming from the engine as it was idling. Acura of Limerick dealership diagnosed the issue coming from the bottom of the engine as a rod knock. They feel the problem is internal to the engine and suggest replacing the engine at my, I the owner's cost. After reviewing blogs and information on recalls on the internet, this issue seems in line with other rod bearing issues with this 3.5L V6 engine. But my Vin is not identified as having the recall issue? This seems incorrect as my Vin should be covered as it seems to be the same problem.

My car has been going into neutral when in the autostop. The only way to get out of it is to turn it off and back on. It's incredibly dangerous. I almost got into a horrible accident. It happens suddenly and without warning.

Email Acura did an update to software for vehicle stalling, but the problem isn't fixed. I have notified the dealer twice and no return call. I am a widow, travel alone and am afraid this vehicle will fail when I'm alone. I was slowing to stop at a stop sign and the car just shut off.

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

I stopped at a red light and when I went to pull of the car cut off. I had to restart the car to pull off. This is the second time that this has happened.

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.

Hi, My 2020 Acura MDX has a problem with a Start/Stop sytem malfunction, sometime it fails to start after start/stop system activated either at the stop sign, red light or non moving traffic on the highway. I have to put it to the park and restart my car. It is very unsafe.

This is the third time this has happened to me and I am very concerned and will be taking my car to Acura YET AGAIN for a checkup. I was driving with my kids in the car and stopped at a red light. When the light changed, I put my foot on the gas and noticed that my car would not move. That’s when I looked down and saw that the car was in neutral. I tried to put it back in drive and it kept telling me to “Shift to Park” and would not let me shift. I panicked as I had several cars behind me on a very busy road but I put my emergency lights on to signal that my car was not operable. After trying again 3 times and turning the car off completely/using keys to lock/unlock doors, it finally turned on and I could drive...

Driving on the highway when suddenly I had lost all power and then the check engine light flashed. I was stranded for hours waiting for.a tow truck and freezing temperatures with no power to my vehicle. It was towed to the nearest Honda dealer and was told I had a complete engine failure and needed a new engine for $10,000.

I had purchased this vehicle and was not aware there was a stop sale on this vehicle model. I took the 2020 MDX to the dealer to get the recall service done, the connecting rod bearing and fuel pump issues. They were done back in March of 2024, j had taken the vehicle back to the dealer over 5 times for issues with stalling and trouble turning back on as well as engine noise, ticking and stalling. The dealer “cannot replicate” the noise all of sudden, but was initially able to hear the noise and stated “ it’s probably fine, but bring it in if it gets worse” this issue happened after the recall service was performed and the vehicle has never been correct since, I believe there is engine damage caused by the needed recall service.

We were traveling far from home on I-44 in Missouri when our 2020 Acura MDX experienced a total engine failure. An engine rod broke and pierced the oil pan causing a sudden loss of engine power. I believe this is related to the NHTSA Investigation #RQ24013, even though the Acura dealership had performed the recall service for this issue a couple months earlier. I suspect the recall service was either performed incorrectly or that a part was not tightened properly, ultimately leading to the engine failure.

There is a clear engine knock. I have a recording of it both on video and audio, my engine performance and gas mileage has gotten worse. I picked up on the sound about 6 weeks ago and called (Mueller Acura), said I would have it checked at the next oil change. The dealer (Mueller Acura of Merrillville) has had my Acura MDX, for two days two weeks ago and for the last 7 days, currently. The didn’t tear down the engine completely. But they told me they had their master mechanic and Honda’s (from another shop Team Honda) Master mechanic came down and used a camera and I have a bad tensioner, bad rockers, and a bad cam shaft. I’ve been speaking with an outside mechanic who is a Honda certified Master mechanic who now runs an independent shop. Acura, says I have a bad camshaft, bad rockers, and bad...

My car is producing a loud noise from the engine bay, which closely resembles the sound of a failing crankshaft. I have taken the vehicle to the dealership several times, but they were unable to determine the source of the noise. I consulted with an experienced mechanic who advised me that the engine is likely to fail soon if the issue is not addressed. He recommended inspecting the internal components of the engine, specifically the crankshaft, for potential faults. I am not sure if the official dealership can check my engine for a faulty crankshaft.

I started to here a very light knocking noise on cold starts. I made an appointment with my dealership to check it out. The earliest appoint they had open was a bout a week out. A few days later I was driving on the highway and the knocking noise suddenly became very loud and all the dashboard lights came on. The vehicle lost power and I barely coasted off the highway before the MDX came to a complete stop. I called AAA and had the car towed to the dealer. The next day they called me and told me it had been a connecting rod bearing failure and needed an entire new engine for $25,000.00. I was in total shock. I googled what happened to me online and found this is happening to many acuras and hondas. The dealer said there is absolutely no warranty and they cant do anything...

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...

Issue with Auto Idle Stop. I have had multiple instances of the auto idle stop kicking in and shutting the car off while I am at a stoplight. This has resulted in VERY close calls with me getting rear ended. I have taken the vehicle in to be inspected at an Acura dealership only to be told that they cannot replicate the issue. When this issue occurs, it takes about a minute to get the car working again. The dashboard lights up with a lot of different flashing lights. There was no warning prior to this issue occurring. You cannot permanently shut off the auto idle stop and I should not be expected to remember to do it every time I get into the vehicle. I am afraid that one day this will cause a bad car accident that will lead to myself or my family getting severely injured/killed as...

The contact owns a 2020 Acura MDX. The contact stated while driving 65 MPH and attempting to stop, the brake pedal was depressed; however, the vehicle failed to respond, and the engine shut off unintendedly. The “Idle Stop” message was displayed on the instrument panel. The vehicle was not taken to be diagnosed or repaired. The manufacturer was notified of the failure. The approximate failure mileage was 54,000.

Auto Idle Mode - After we've stopped and released the brake to go forward, the car will then shift to neutral by itself instead of restarting to drive. This has happened frequently and is now starting to happen more often. This is a safety issue, especially if you're the last car in line and other cars are traveling 55-60 miles behind you on a major road and see a green light ahead. Each time this happens, we have to turn off the car and try to restart the car, and sometimes this has been iffy and we've had to repeat the process a couple of times. There were no warning lights of problems with any of car components. There have been similar reports of this occurring: [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

The auto idle engine stop malfuctions routinely shutting the engine off completely and requiring the driver to engage PARK, hit STOP, and RESTART engine before engaging DRIVE to proceed. We have experienced several near miss accidents or potentially caused accidents because drivers behind you have no idea what is going on. This issue is not just at stop lights but also interstate driving where traffic comes to a complete stop. I requested my Acura dealer permanantly disable this feature- they declined - I believe because it is an "Emission" feature that has gone wrong. I have seen "hack" options on line to disable this feature but fear for my safety - either way.

My MDX will randomly shut itself off while at a red light. It takes MULTIPLE attempts to get it restarted. The vehicle is available for inspection upon request. My safety and the safety of others was put at risk and continues to be at risk! This has happened at a highway red light multiple times. I am impeding the flow of traffic at an intersection with EIGHT lanes and FOUR lanes cross traffic. People move through this intersection extremely fast. This puts me at risk of causing an accident, injury the occupants of my vehicle and the occupants of the other involved vehicles. There is no warning as to when this will occur and there are no warnings at the time of the actual event either. I called the dealership and the service department acknowledged there have been others with the same issue. Acura is aware of the issue yet...

WHEN I WAS STOPPED AT A RED LIGHT IN TRAFFIC (MY VEHICLE WAS IN IDLE STOP MODE), MY CAR SIMPLY DIED AND WOULD NOT RESTART WHEN THE TRAFFIC LIGHT TURNED GREEN AND I STEPPED ON THE GAS PEDAL TO MOVE FORWARD WITH TRAFFIC. IT TOOK NUMEROUS ATTEMPTS TO RE START THE VEHICLE WHILE STUCK IN VERY HEAVY TRAFFIC BEFORE IT GAINED POWER AND WAS ABLE TO DRIVE FORWARD. MY SAFETY WAS COMPROMISED I WAS IN THE MIDDLE OF MULTIPLE LANES OF MOVING TRAFFIC, IT WAS SCARY. NO WARNING LAMPS OR MESSAGES OCCURED PRIOR TO THE INCIDENT.

I was in traffic and we slowed down to a stop. Suddenly my car went to neutral and it didn’t want to go to Drive. I put emergency lights, as many cars were behind in the highway. I turned the car off and turned it back on. Then I was able to drive again! This has happened twice in the last 3 months.

No warning lights or other indications occurred. This is the 2nd time while sitting at a stop light that the car has gone into neutral gear and it was unknown until the traffic signal turned green and I could not go. I could not shift into drive. The remedy required that I shut the car off and restarted (very little time between) before putting it in gear. Both occurrences were with idle stop function on. There is an entire discussion forum on this exact issue on [XXX] . Being first in line at a stop with 4 other passengers and a line of drivers expecting me to go on green is a sure way to result in an accident. The car goes in for regular service next week and I will bring it to the dealer’s attention. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

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.

Engine shuts off at red light as auto idle stop got activated. Then at green light when I press the accelerator my car was in”neutral”mode and it didn’t allow me to move. I had to put my car into parking then switch it off and restart it. People behind me were agitated and honking.

the vehicle shut down while at a red light and went the transmission went into neutral and should not start until i place the vehicle into park and then i had to press the start button two or three times to get the vehicle to start again. this is the second time this same problem has occurred in a two week span

Persistent Idle Start issue not being addressed by the Acura dealership despite multiple trips to the dealership with the same issue. My SUV intermittently shuts down in the middle of busy intersections leaving me at great risk for a crash and bodily harm. There is a Service Bulletin issued in January 2023 by Acura admitting to the issue and it shows how Acura will resolve the issue for affected vehicles. Unfortunately Acura is not following their own Service Bulletin, and a recall of these vehicles needs to be issued to address the affected vehicles. I am requesting the NHTSA to take immediate action and issue a recall for this known idle start issue that is putting many Acura drivers at increased risk for bodily harm.

upon turning right, the car lost power, degraded acceleration as if someone is holding and pulling the car to move forward. The traffic behind me expected me to cathup with the speed on the road but due to loss of power and engine hesitation i got honked and was luck to avoid a crash from behind on a busy road. Acura dealership in Dallas dont have parts since a very long time. They have pleant of new cars to sell but not repair.