New 2020 Suburban w/775 miles - loss of steering assist, all gears but 1, etc.

[JohnnyR]

Man - I must have won the prize for dud purchase! I'm open to any and all suggestions for how to deal with this:

Long time Chevy purchaser/owner here. Just picked up a new 2020 Suburban LT w/5.3 in late January '20. Less than two weeks and 800 miles into ownership, it threw multiple codes upon start-up.

I lost steering assist, StabiliTrak, all gears but 1st (no reverse, no manual shift mode), tow/haul mode, trailer brake system, seat heat. The tach and speedometer were inop as well (just stayed pegged to the bottom).

Five minutes and six restarts later, it ran fine. Called dealer and arranged to bring in the next morning. Next morning, same issue upon start. Approximately twenty attempts and still in limp mode, so arranged for tow. Turned truck to "on" a few minutes later in order to read mileage and no codes exhibited, so I started it without issue and drove to dealer.

The dealer's maintenance crew can't reproduce the issue and they are unwilling to simply replace ECM's/TCM's.

Sigh... I have a feeling I'm in for a nightmare of chasing electrical gremlins. It's supposed to be our family vehicle for travel to camp up in northern Maine. No way am I trusting this thing with my kids or back in the sticks, with all the potential for failure engineered into the electrical system. After now reading here on this forum about the steering and electrical issues of this platform, I'm pretty bummed at the ownership ahead of me.

You can read my NHTSA ID Number: 11307573 report at this link. https://www.nhtsa.gov/vehicle/2020/CHEVROLET/SUBURBAN%25201500/SUV/4WD
Thanks,
Johnny
Boston, Massachusetts

 

[Doubeleive]

my best suggestion would be next time it happens pull out your phone and record it, that way you have some evidence to show

 

[JohnnyR]

Will definitely do that...

 

[Doubeleive]

Will definitely do that...

You shouldn't be having these kinds of issue's on a brand new truck but they are known to be finicky when there is power problems, such as a bad battery or battery cables, there are some TSB's out there for similar or related issue's, a TSB is not a recall but is a technical bulletin that they put out to the tech's when they find a potential issue, some of them involve replacing battery cables and others are checking various connections or even a "calibration firmware update".

 

[gat0r]

you need to talk to service manager & have them get a competent mechanic to look at it.
sounds like they had an oil change monkey look at it

should be codes stored in the system.

there are known TSBs for steering.
have them check for grounding issues. (cut wires, loose connections)

 

[JohnnyR]

Hopefully it's gone higher than the bottom tier mechanics. They've had it for three days.

I forwarded the VIN of a similar NHTSA case of a 2019 Tahoe w/exactly same symptoms. They should be able to research and find the issue between that and the TSB's. Maybe...

you need to talk to service manager & have them get a competent mechanic to look at it.
sounds like they had an oil change monkey look at it

should be codes stored in the system.

there are known TSBs for steering.
have them check for grounding issues. (cut wires, loose connections)

 

[JohnnyR]

Good news: they tried starting it with remote start this a.m. and all failure modes exhibited, so they are actively checking to see where errors are generating.

 

[JB11]

Good news: they tried starting it with remote start this a.m. and all failure modes exhibited, so they are actively checking to see where errors are generating.

Keep us updated

 

[GTNator]

Hopefully it’s just a software issue that can be fixed with a fresh flash of the computer.


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[JohnnyR]

Communication module (for Onstar and remote start) that went tango uniform.
Pretty lame that a non-essential feature failure could make entire vehicle inop.
Never again am I buying a modern vehicle for camping, road tripping in backwoods areas, etc.

 

[BlaineBug]

https://www.tahoeyukonforum.com/thr...ressure-no-power-steering-second-time.116543/

Does my issue sound similar to yours? 2019 GMC Yukon SLT 4x4.

I have also just submitted a complaint with the NHTSA today since this issue occurred on two occasions now, 5-6 weeks after the first time it went in to the dealership for this problem.

By reading our description our issues are not exact but do share many common similarities. Please see my thread and watch the video.

 

[JohnnyR]

See my response to your thread. Absolutely nuts that a Bluetooth-wifi module could inop an entire system/vehicle.
Failed module on my 2020 Suburban was 84293872. Failed when vehicle remote started.

 

[BlaineBug]

How were you starting the truck, with the keyfob or the remote start through the Onstar phone app? I have heard of issues with the 2019/2020 Silverado and Sierra trucks when starting through the Onstar phone app that was caused by a recent software update. But I don't even have active Onstar on my 2019 so I can't possibly remote start it with the app.

What pointed them in the direction of the bluetooth-wifi module as being the culprit?

My 2019 yukon did not have any active codes the first time, only history codes. And this second time they are saying no codes as well, just one "U" code of unknown. This was just on Friday afternoon so much much was done yet I would assume.

 

[JohnnyR]

Keep in mind that this is a conventional ignition (not keyless with pushbutton start).

I don't use the app. My phone folds in half!
It was the fob remote start. The error occurred even after vehicle had shut itself off from running past the time limit in remote start, and then I inserted key (don't have keyless start in this LT) and started manually.

It did not happen every time - maybe every 5th or 6th remote start.

They were only able to narrow it down to that module by replicating the problem at the dealership and leaving it running and hooking up their diagnostics. They were able to previously pull the resident error codes but those did not indicate where the error was originating.

I would say that if it occurs again, don't shut it off and do insist that the tow/flatbed guy leave it running until the dealership can hook up their diagnostics while it's still in "failure mode."

How were you starting the truck, with the keyfob or the remote start through the Onstar phone app? I have heard of issues with the 2019/2020 Silverado and Sierra trucks when starting through the Onstar phone app that was caused by a recent software update. But I don't even have active Onstar on my 2019 so I can't possibly remote start it with the app.

What pointed them in the direction of the bluetooth-wifi module as being the culprit?

My 2019 yukon did not have any active codes the first time, only history codes. And this second time they are saying no codes as well, just one "U" code of unknown. This was just on Friday afternoon so much much was done yet I would assume.

 

[BlaineBug]

By the way Johnny, I am not seeing your response to my thread. When did you post it?

That's a good idea about leaving the vehicle running but the only problem is, the first time it occurred, by the time the tow picked it up their service center was closed for the evening.

This time I begged and pleaded on the phone to have someone come out and hook up while I was experiencing the issue as I was only 15 minutes away from the dealership. They told me they didn't offer that service and only roadside assistance could help me.

It's not just us, there were a couple of other 2019 owners with the same problem, where it always will return to normal just as if nothing happened, and then the dealership replaces some random part and crosses their fingers.

By the way I haven't used my remote start lately so it doesn't seem to be related to that at all, at least for me. Are you saying that each and every time you encountered this issue, you had just used the remote start? I didn't realize that 2020 models came with non-push button start, either.

 

[Doubeleive]

HEHE wait till they bust out the android based 2021's then your really going to see some screw ball shit

 

[Bob2C]

What’s with these issues popping up? Have been following @BlaineBug on his issues. I’m still leaning battery cables or main ground cable behind engine on driver side.

And I thought I had issues with a rough idle which by the way I fixed by raising the idle 100 RPM’s


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[BlaineBug]

What’s with these issues popping up? Have been following @BlaineBug on his issues. I’m still leaning battery cables or main ground cable behind engine on driver side.

And I thought I had issues with a rough idle which by the way I fixed by raising the idle 100 RPM’s


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TSB # 18-NA-161 specifically mentions checking resistance of all of the battery cables. The last time I was in the shop that's the TSB they mentioned on the service invoice. One would think they made all of the proper checks? Even with a cable that has high resistance, what's the deal with having to press the start button two times in order to get the infotainment and dash backlighting to turn on, after the engine is running? I can't wait to hear their BS response this time.