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There are several situations that will not activate the Auto Stop Feature. A/C load is one among a long list. Mine however when it does decide to work, it works when A/C is on and when the engine light was on once which it should not work at all. GM cannot figure it out. When the Auto Stop Feature is not working at all, the volt meter is around 15-17 volt when running down the road. When the Auto stop feature is working properly then the volt meter holds and 13 volts running down the road.

Unplugging my camera did work a couple of times but since it does not make any difference. Pay attention to your volt meter as mine is at 15-17 when the Auto Stop feature inst working. After dealer clears or resets the ECM the volt meter returns to 10-12 and Auto Stop works again. I am hoping that the new ECM once installed will fix the issue.

Update on my 2019 1500 GMC for anyone who cares. Auto stop still not functioning correctly. 23,000 miles so for and truck still running great. Noticed cruising down the highway around 65 miles an hour the engine light started flashing slowly. Light stopped after 5 miles and the truck never missed a beat. Called dealer and they said bring it in right away as the flashing light can be serious. Anyways long story short the dealer has ordered a new ECM and stated that that may be the problem all along. IDK but I am definitely purchasing an extended warranty!!! ECM is on order and will not be in for a week or so. Dealer let me take my truck and asked me to keep an eye on the engine light. Auto stop is now working again for the time being. Love the truck and ride but getting aggravated as to what is continually going on with the Auto Stop feature.

Same here with recalls and updates. Still having intermittent troubles with mine. I have found when the Auto Stop quits, I unplug my dash camera for a few miles. Sounds crazy but it works after I plug it back in. Really concerned about the electronics on this truck. I also have had the engine light come on recently and dealer stated the same “an open circuit” but unable to identify. Auto Stop was still working even though engine light was on. The other day when I started the truck the brake pedal went to the floor and message on dash said “Critical Brake Failure” but soon went off. I will need to ask about that message. I have read other threads and they state that aftermarket plugs that are plugged into the accessories ports will mess with the Auto Stop Feature. 19,000 Miles and still having issues. I really love the truck and will keep driving but once Manufacturer’s warranty nears the end I will purchase extended warranty my dealer offers. Keep me updated on yours.

Every part on the truck is original.

Auto stop is still working but now the engine light is coming on and volt meter jumps from 12 to 14 volts rapidly back and forth which did not do that prior to the engine light illuminating. Yes auto stop is still working even though the engine light is on and should not from what I understand. Dealer said it is some between the steering wheel and the electric brakes causing the light to come on. Dealer said it could be as simply as a brake light. Really getting concerned about this truck having electrical issues. Still love the ride and the 20 MPG it is getting.

Last time GM tech said my battery was below 75% so they charged it up and has been working now for the past 400 miles. I am not sure if that is the permanent fix as this problem started at 500 miles and truck has been in the shop four separate times for this issue. Truck now has 16,000 miles and will see how long it works this time. I would charge the battery and see if that could be it.

Did you find out what the problem is! I am having the same issue.

Did you find out what the issue is? I am having same troubles.

I have a new 2019 Sierra that the Auto Stop did not work after the first 500 miles. I have had it in the shop 4 separate times and the GM techs cannot figure it out. Each time GM resets it and it works for 300 miles or less then stops working again. Now this is strange as we got 6” of snow and the first time I put the truck in 4x4 I noticed the Auto Stop started working after I shifted back to 2 wheel drive. Truck has 16,000 miles and I will let the dealer know that it is working now but hopefully it is not a problem in the future.

2019 gmc x31 same issue. Dealer and GM cannot figure it out yet. Some sort of fault showing in ecm. Once reset auto stop works as it should for 100 to 300 miles then quits again. At dealer 4 seperate times for this issue. Now the dealer wants me to leave the truck and give me a loaner until GM figures it out.