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Idle Stop - Randomly Turning off Engine at Stop Lights

5213 Views 59 Replies 22 Participants Last post by  whtmtn
I drive a 2019 w/ Tech Pkg with 50K mileage. It comes with Idle Stop. About once a day now, the Idle Stop engages, turns off engine as intended BUT then the Car shifts into Neutral and the engine fully dies. I'm left at stop lights or stop signs with a car that is off and will not restart. I'm so tired of this happening.

My dealership said that Acura acknowledged a similar issue on TLX and pushed a software update to fix Idle Stop. They gave me the Acura complaint phone number (LOL). Coming here to complain first...

Is anyone else having this issue? I'm now searching for a 2018 MDX to avoid any Idle Stop functionality. Yes, I know I can turn it off but I forget, and then have this issue. Very frustrating and not safe. I was almost rear ended today!
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Couple others also reported the same issue on this forum, I have a 2016 ADV with Idle stop and I never experienced the issue since I owned it(over 18 months now).
Yes, Acura is aware of the issue and few TLX owners seem to have received warranty extension letter on starter motors.
Try either being more insistent that the dealership examine the vehicle for a fault or take it to another dealership to look at. From your description it sounds as if they didn't even look at the vehicle and just said they heard of some other vehicle exhibiting the issue, which doesn't help anyone and isn't relevant to your issue.

A decent mechanic needs to actually check out the vehicle to find out what's going on. Keep in mind that many Service Advisors don't actually know much about the mechanics of a vehicle so don't let them decide what to do - it needs to be seen by a mechanic.
Weird how some go haywire and some don't. My 18 Advance has never done what you described. Just have dealer fix under warranty. Not cool! Here's a longshot thing you can try... Transmission memory reset. With car off, turn ignition to acc so engine is not started, then press accelerator to floor until light light goes out. Turn car off. Then start as normal. Probly won't fix your issue but worth a try?
I drive a 2019 w/ Tech Pkg with 50K mileage. It comes with Idle Stop. About once a day now, the Idle Stop engages, turns off engine as intended BUT then the Car shifts into Neutral and the engine fully dies. I'm left at stop lights or stop signs with a car that is off and will not restart. I'm so tired of this happening.

My dealership said that Acura acknowledged a similar issue on TLX and pushed a software update to fix Idle Stop. They gave me the Acura complaint phone number (LOL). Coming here to complain first...

Is anyone else having this issue? I'm now searching for a 2018 MDX to avoid any Idle Stop functionality. Yes, I know I can turn it off but I forget, and then have this issue. Very frustrating and not safe. I was almost rear ended today!
Having the exact same issue with my 2019. Been discussing in this forum:

At the dealer for the fourth time and waiting to hear if they have a solution. Mine happens in hot weather or when the engine is hot. Took the car in 3x last year and they could not duplicate the problem or find an engine fault. Have report it to both American Honda and NTSA. I believe it started following the recall replacement of the fuel pump which I did in July of 2021 just before the issue started happening. Did you do a fuel pump replacement? IMO two things are critical in the restart process, battery and fuel pump. The fuel pump was replaced under the recall and the battery was replaced after the issue began therefore I believe it has something to do with that replacement. Dealer has said no but we shall see.
Having the exact same issue with my 2019. Been discussing in this forum:

At the dealer for the fourth time and waiting to hear if they have a solution. Mine happens in hot weather or when the engine is hot. Took the car in 3x last year and they could not duplicate the problem or find an engine fault. Have report it to both American Honda and NTSA. I believe it started following the recall replacement of the fuel pump which I did in July of 2021 just before the issue started happening. Did you do a fuel pump replacement? IMO two things are critical in the restart process, battery and fuel pump. The fuel pump was replaced under the recall and the battery was replaced after the issue began therefore I believe it has something to do with that replacement. Dealer has said no but we shall see.
There's a lawsuit in California Federal court filed by Hamid Bolooki last month. Perhaps it will get the ball rolling on this problem. Grateful I've never had the issue but foresee it happening some day.
There's a lawsuit in California Federal court filed by Hamid Bolooki last month. Perhaps it will get the ball rolling on this problem. Grateful I've never had the issue but foresee it happening some day.
Thank you for the heads up. Sounds like the same problem and disappointed they don't have a solution. I found the following description of the suit online at:
I drive a 2019 w/ Tech Pkg with 50K mileage. It comes with Idle Stop. About once a day now, the Idle Stop engages, turns off engine as intended BUT then the Car shifts into Neutral and the engine fully dies. I'm left at stop lights or stop signs with a car that is off and will not restart. I'm so tired of this happening.

My dealership said that Acura acknowledged a similar issue on TLX and pushed a software update to fix Idle Stop. They gave me the Acura complaint phone number (LOL). Coming here to complain first...

Is anyone else having this issue? I'm now searching for a 2018 MDX to avoid any Idle Stop functionality. Yes, I know I can turn it off but I forget, and then have this issue. Very frustrating and not safe. I was almost rear ended today!
This is also the sign of a dying battery, especially if the battery has never been replaced since the car was new in 2019. They only last about 3 years and problems with Idle Stop are the first signs that it's on the way out. I recommend just turning Idle Stop off whenever you drive the car, and get the battery tested.
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Same thing has happened to me 3 times in my 2020 mdx. They replaced the battery, but it happened again after the new battery. The service department kept my car for three days and couldn't replicate the problem and all diagnostics came back clean. Also, more recently, while driving the main info screen went black but displayed the reverse yellow lines (I was not in reverse). Clearly something is happening with the computer in addition to the auto idle stop causing problems.
Same thing has happened to me 3 times in my 2020 mdx. They replaced the battery, but it happened again after the new battery. The service department kept my car for three days and couldn't replicate the problem and all diagnostics came back clean. Also, more recently, while driving the main info screen
Same thing has happened to me 3 times in my 2020 mdx. They replaced the battery, but it happened again after the new battery. The service department kept my car for three days and couldn't replicate the problem and all diagnostics came back clean. Also, more recently, while driving the main info screen went black but displayed the reverse yellow lines (I was not in reverse). Clearly something is happening with the computer in addition to the auto idle stop causing problems.
went black but displayed the reverse yellow lines (I was not in reverse). Clearly something is happening with the computer in addition to the auto idle stop causing problems.
Same thing has happened to me 3 times in my 2020 mdx. They replaced the battery, but it happened again after the new battery. The service department kept my car for three days and couldn't replicate the problem and all diagnostics came back clean. Also, more recently, while driving the main info screen went black but displayed the reverse yellow lines (I was not in reverse). Clearly something is happening with the computer in addition to the auto idle stop causing problems.
Had this exact issue and they cannot diagnose. You should report it to the NHTSA if you haven't already and contact American Honda. If enough people do maybe something will be done. 2020 ACURA MDX SUV AWD | NHTSA
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I saw that Acura just published a software update for this. Dealers will apply it for free (special warranty extension) for 10 years after purchase, unlimited miles.

TSB 23-001 - Product Update: 2016-20 MDX PGM-FI Idle Stop Software Update
I saw that Acura just published a software update for this. Dealers will apply it for free (special warranty extension) for 10 years after purchase, unlimited miles.

TSB 23-001 - Product Update: 2016-20 MDX PGM-FI Idle Stop Software Update
This is great news! Amazed that the dealers had no clue but I suppose with more aspect’s being software driven I am not surprised. Curious if it’s a recall or do you have to request the service.
If you read the bulletin, it is very clear what is happening. People with an aged battery who don't use a trickle charger are having a restart issue. The computer is allowing a restart with insufficient battery power. If you have a newer battery or if you trickle charge your older battery, this really shouldn't be an issue. With an Advance model, let's say you have your heated steer wheel on, heated seats, heated windshield ribbon, headlights, fog lights, brake lights, radio and blower motor all going with the motor off, that battery is gonna drain quick.
If you read the bulletin, it is very clear what is happening. People with an aged battery who don't use a trickle charger are having a restart issue. The computer is allowing a restart with insufficient battery power. If you have a newer battery or if you trickle charge your older battery, this really shouldn't be an issue. With an Advance model, let's say you have your heated steer wheel on, heated seats, heated windshield ribbon, headlights, fog lights, brake lights, radio and blower motor all going with the motor off, that battery is gonna drain quick.
Happened to me even after the dealer supposedly replaced my battery on a new low mileage 2019 MDX. So there’s that.
Another one below TSB 23-002 - Warranty Extension: Engine Does Not Auto Restart After Entering Auto Idle Stop
http://www.urvi.net/forumfiles/SB/B23-002.PDF
Wow, free replacement starter and valve adjustment. Lawyers and/or nhtsa must have spooked them.

Doesn't apply to hybrids so I guess I'm out of luck.
Happened to me even after the dealer supposedly replaced my battery on a new low mileage 2019 MDX. So there’s that.
If you experienced a no restart with a fresh battery, it does not appear this service bulletin will fix your issue. The service bulletin clearly indicates the operation performed is an adjustment of the operating range (voltage) with a direct correlation to older batteries. Your issue seems to be electrical and not due to a low battery. You could have a loose ground or other unknown issue. For everyone else who experiences low voltage and a failed restart, this software modification will help to disable the auto stop when a 12v battery is low, by lowering the voltage threshold.
The 01 TSB is low battery voltage. The 02 TSB is a free replacement starter and valve adjustment to presumably reduce battery draw.
The 01 TSB is low battery voltage. The 02 TSB is a free replacement starter and valve adjustment to presumably reduce battery draw.
After 3 visits and supposed battery replacement the dealer could not figure out the problem. One thing they said was that the type of battery Acura was using in these vehicles might not be strong enough. I resigned to always turning the auto shutoff off each time I drove the car. May never know what the real problem is but I suspect it may be the batteries they are using. I say supposedly changed my battery because I didn’t see much evidence around the engine(dust disturbance) that they had done it and I questioned it. The service rep was gone a few weeks later. Second the car does take more turns to start, particularly after sitting or in cold weather, more than a new car should and based on my experience of many years and new vehicles. Glad I don’t live too far north. 🙂
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