[vidguy]

My daughter and Son in law have a 2015 Suburban. Recently the CEL and other lights started coming on mainly in the morning, but would run ok and the light would go out. This according to my daughter.
This morning she got a few houses away after starting it up and "all the lights came on". She drove it back and parked it. We trailered it to the dealer. She called and said they told her:
"There is no code and the last thing the ECM recorded was a low voltage. But the battery and alternator check out".
Would this be the ECM failing?
Any experience with these vehicles here? Just out of warranty.

Thanks

[dataway]

If you are in far northern climes ... it's kind of normal. My 2011 GMC and numerous others I have talked to with late model cars ... start them up at 10 below zero and all the lights come on. Ignore them, car warms up, go to work, come back out to go home, all the lights are out.
Typically it's all the ABS, traction control, stabili-trac, etc.

[vidguy]

WE're in Warm California, but it has been chilly in the AM, 40 degrees...
So this is kinda common and you think it is generally related to the ABS, Traction Control huh?

[dataway]

Sounds like a different problem. I'm talking COLD ... it only seems to happen to vehicles up here when it gets to around 10 below zero.

Hard to believe it didn't hold some codes .... you should probably get a decent scanner and check yourself. Typically all the ABS etc. is controlled by the chassis computer, usually doesn't trigger a CEL.

If it's doing all that ..... yeah, maybe a bad ECM ... or a ground going bad somewhere. If it's not storing a code ... jeez, all you can really do is drive it till something fails or it stores a hard code of some kind that will give you a clue.

[jerry455]

If it is not storing codes it is probably a ground or a battery. A batteries life can be anywhere from 2 -8 years. I would get the battery load tested. Check battery terminal connections.

[77 Canamman]

Check battery cables. They seem to be an issue on late model GM trucks. Other causes include a flaky ECM/BCM.

Since it isn't showing codes, a loss of voltage seems likely.

[vidguy]

Thanks. I'll check the cables then. Dealer said the Battery Checked out...
Anyway to verify the ECM or the Body Control Module? Those BCM's look to be an expensive crap shoot?
The ECM doesnt seem to cost as much..

[skipp65]

I’d replace the battery, it’s 4 going on 5 years old and when going bad aren’t always consistent. If that isn’t the problem it isn’t really wasted money because it would one soon anyway. I’ve seen bad batteries do some funky things and still test ok.

[jerry455]

ECMs and BCMs are not common failure items. They are also expensive and have to be programmed to the vehicle. Like someone commented earlier, I would get a new battery and make sure cables are tight. A failing battery can cause those symptoms.

[muscle_collector]

my HD2500 did this and then started other things like ac blowing hot , heat blowing outside temp, drove me crazy and nobody could seem to figure it out. until my water pump went out and i was lucky to be about a mile from a friends diesel shop that works on semis and equipment. he said they were kinda slow and would be happy to replace the pump for me. when i came back the next day he said oh by the way i fixed your problem with the gauges hvac etc... turned out to be a hot wire coming out of the fuse box the insulation was just cut a bit short and it was grounding itself. it has never given me another problem since he fixed it.

[vidguy]

The dealer ended up replacing the ECM after trying to keep the car for more testing..when we told them it must be the ECM if its not the charging system/wiring.

That did the trick.. Thanks guys.

Gotta say the dealership treatment was very poor... Bad Attitude, no communication, didn't want to replace the part. Only offered a SONIC loaner car for one day while they had the SUBURBAN for four days.

Took loud demands by my Son-in-law and all that my Daughter, with two 5 month old twins NEEDS that truck... or one large enough for the family to ride in safely.

[ponjohn]

IF it is the original battery I would replace it.

[Chris65LeMans]

Back in 1995, I blew out a synchro in my Honda 5 speed (brand new car) while racing on the freeway. Dealer after dealer refused to fix it due to the “aftermarket stereo, or suspension” or some other b.s. (drivetrain was stock.). I asked around, and was told of a friendly dealer about an hour drive away. They were happy to fix it.

Point is - if you’re getting lousy warranty service from one Chevy dealer, it’s probably a good idea to try a different one.

[dataway]

When my 2011 GMC wipers self destructed during the winter I went to the dealer where I bought it and wanted it fixed. The newbie service manager asked me if they were frozen to the window .. I said ..."Duhh... it's freakin February in upstate ny so... probably yes" so he said it wasn't covered ... so I said ...you sold me a vehicle in upstate ny that has wipers that self destruct when they freeze?

I emailed GM ... told them, they called the dealer ... literally two hours later the dealer calls me up, very politely says bring it in, they will fix it under warranty.

Turns out the "over current" or "over-load" or whatever on the wipers didn't work so it broke the wiper drive train ... they fixed, it, and it's worked fine ever since. Now if they are frozen they do what they are supposed to ... it overloads and shuts down the wiper motor until the wipers are free to move.

Point being, yes ... explore other dealers or call the manufacturer ... evidently they take warranty claims pretty seriously and will put the boots to a dealer giving a customer a hard time.

[vidguy]

Yes another dealer will be used for any future work.
I did tell him to call GM CS and let them know about the experience.