21' Suburban HC - Electronics went bananas.

[MrScrewzloose]

Hey All,

I figured I'd drop a note here just in case someone else had gone through this issue and worked through to resolution. Unfortunately, my local Chevy dealer's service department is way behind, earliest I can get in is almost a month out.

my truck: 2021 Suburban HC 6.2L

What happened?

- Yesterday morning, started the truck as normal, got a Low Battery Warning and also got a Service Driver Assist System error. From the looks of it, my lane assist and forward camera system stopped working. Later that morning, 2nd restart, same errors.

- I went home, checked the battery, was showing about 12.46v, low but not terrible. Disconnected all the vehicle leads to the battery and put the battery on a charger.

- Came back about 2hrs later, charger showed it was in float mode and the battery was fully charged. Reconnected all the vehicle leads to the positive/negative. Started trucked and now in addition Service Driver Assist System error, my entire Infotainment screen is black and the controls below are no longer illuminated. Turned the truck off, exited vehicle, then re-entered and restarted and every error in the book began to flash on the dash screen. So many errors.

- I came back to the truck a few hours later. Truck refused to crank. Numerous errors popped up again. I pulled on my OBDII scan system, over 43 fault codes across 14 systems.

- In my 2016 Tahoe, I saw a similar issue with a dieing battery causing an array of electronic malfunctions. So I replaced the battery. I no longer get the array of errors, however, my Infotainment system still does not power on. Nor do I have sound when my indicators/blinkers are used (I wasn't aware the indicator sound was piped through the speakers). I've attempted every button "reset" procedure I could find on the internet but nothing worked.

- I've done a continuity test on every fuse in the engine bay, passenger side, and rear. Nothing blown that I could find.

Question:

- Anyone know where the modules are located that serve as the hub for the Infotainment center?
- Any bright ideas?


Thank you!

 

[StephenPT]

So at this point you've replaced the battery, everything is back to normal except the infotainment screen won't boot and you don't have a blinker sound?

Have you tried using the physical buttons just below the infotainment screen? There's a power button, home button, skip track, etc. Can you get any of those buttons to turn on the radio, or screen? I know in my Honda Accord when I replaced the battery the infotainment screen was locked out. Doing a bit of searching I found that pressing and holding the power button resynced the infotainment with the car and unlocked it.

I believe the radio/infotainment module is located to the outboard side of the glovebox.

 

[MrScrewzloose]

Thanks.

At this point, the Infotainment system does not power on. The physical buttons below, as you mentioned, power, home, skip, etc. Do not function either, nor do they illuminate. I've pressed every reset combo on those buttons I could find without success.

As for the indicator/blinker, those do still work, but the audible "clicking" sound you generally hear when using them does not. I guess those are tied into the audio system/speakers.

 

[StephenPT]

Might just need to take it to the dealer and get the radio reprogrammed?

https://static.nhtsa.gov/odi/tsbs/2021/MC-10197327-9999.pdf

 

[MrScrewzloose]

Might just need to take it to the dealer and get the radio reprogrammed?

https://static.nhtsa.gov/odi/tsbs/2021/MC-10197327-9999.pdf

Yea, this may be the case.. but given I can't get into service till mid-December, was seeking alternative resolutions.

 

[Doubeleive]

disconnect battery again and re-try, this time when you have the cables off either touch the cables together for a few seconds and/or just go inside the truck and hit every button/switch/pedal to dissipate any remaining power, then reconnect the battery.

I would guess the radio (mostbus) probably did not get a good handshake when the power was disconnected the last couple times.

 

[RST Dana]

Yea, this may be the case.. but given I can't into service till mid-December, was seeking alternative resolutions.

Ouch. I’m spoiled with my dealer. I don’t have to wait for appointments. If I thought there was going to be an issue, I call the service mgr before I head there.

 

[StormTrooprSubZ71]

Yea, this may be the case.. but given I can't get into service till mid-December, was seeking alternative resolutions.

No other Dealers close by? My local dealer was backed up 3 weeks for any service. A dealer 20 minutes away took me in the next day.

 

[MrScrewzloose]

disconnect battery again and re-try, this time when you have the cables off either touch the cables together for a few seconds and/or just go inside the truck and hit every button/switch/pedal to dissipate any remaining power, then reconnect the battery.

I would guess the radio (mostbus) probably did not get a good handshake when the power was disconnected the last couple times.

I gave it a go, no dice. Unfortunately.

No other Dealers close by? My local dealer was backed up 3 weeks for any service. A dealer 20 minutes away took me in the next day.

There's two others in the area; however their reviews are abysmal.

 

[Doubeleive]

I gave it a go, no dice. Unfortunately.



There's two others in the area; however their reviews are abysmal.

ya your code list is showing the open code for telematics, you might try digging around the web for where the radio grounds are and fuses, might get lucky

 

[MrScrewzloose]

ya your code list is showing the open code for telematics, you might try digging around the web for where the radio grounds are and fuses, might get lucky

New scan; we're down to half the fault codes, still have the telematics as you saw above.

B1B2F00‑00 Radio Audio/Video Communication Lost

Thanks for the suggestions so far.

 

[Doubeleive]

New scan; we're down to half the fault codes, still have the telematics as you saw above.

B1B2F00‑00 Radio Audio/Video Communication Lost

Thanks for the suggestions so far.

View attachment 414366
View attachment 414367

telematics is the only open code though, and still showing low voltage
i would use a meter and check the voltage at the battery and then check it again at the obd port, just to see if there is a drop somewhere in between
maybe also check it at the radio fuse, my guess is there is a poor connection somewhere it's kind of hard to kill a radio by just changing the battery.
I am not real familiar with the 21+ battery top terminal but if it is like the previous years there should be a fuseable link with multiple power wires attached maybe try cleaning those up and check each link for power in case one somehow popped.

 

[MrScrewzloose]

telematics is the only open code though, and still showing low voltage
i would use a meter and check the voltage at the battery and then check it again at the obd port, just to see if there is a drop somewhere in between
maybe also check it at the radio fuse, my guess is there is a poor connection somewhere it's kind of hard to kill a radio by just changing the battery.
I am not real familiar with the 21+ battery top terminal but if it is like the previous years there should be a fuseable link with multiple power wires attached maybe try cleaning those up and check each link for power in case one somehow popped.

Thanks.

Solid voltage at both the battery (new) and at the OBD port. Also checked each of the 3 leads coming off the positive battery terminal, both with engine off and on, to check the alternator. All solid readings. Though the lead contacts were clean, gave a additional clean none the less.

Though continuity across all fuses in each of the three fuse panels were good, I went ahead and replaced the 2x TCM fuses (engine and passenger side), just for the hell of it, no luck.

I cleared all of the historical codes. Drove for about 20min and now have a persistent CEL which is new. Remaining active trouble codes are:

Engine Control Module(ECM):
U220F00‑00 - Serial Data Gateway Module Lost Communication with Transmission Control Module

Telematics Control Module(TCICM):
U100800‑00 - Loss of Ethernet Link
B1B2F00‑00 - Radio Audio/Video Communication Lost

Something is up with the TCM module, or so it seems. I guess I'll just need to deal with it until I get the truck into service.

Thanks again

 

[Doubeleive]

Thanks.

Solid voltage at both the battery (new) and at the OBD port. Also checked each of the 3 leads coming off the positive battery terminal, both with engine off and on, to check the alternator. All solid readings. Though the lead contacts were clean, gave a additional clean none the less.

Though continuity across all fuses in each of the three fuse panels were good, I went ahead and replaced the 2x TCM fuses (engine and passenger side), just for the hell of it, no luck.

I cleared all of the historical codes. Drove for about 20min and now have a persistent CEL which is new. Remaining active trouble codes are:

Engine Control Module(ECM):
U220F00‑00 - Serial Data Gateway Module Lost Communication with Transmission Control Module

Telematics Control Module(TCICM):
U100800‑00 - Loss of Ethernet Link
B1B2F00‑00 - Radio Audio/Video Communication Lost

Something is up with the TCM module, or so it seems. I guess I'll just need to deal with it until I get the truck into service.

Thanks again

If you pulled the tcm fuse with the battery connected that might explain the tcm error
I would try disconnecting the battery again, but this time leave it disconnected for at least 10 minutes (go 20) to be sure
maybe while the battery is disconnected check the radio harness's in the drivers left rear compartment area where the jack storage is, see if anything came loose or is not correctly seated.
if still nothing, then maybe try hitting the google speech button if you have one on your steering wheel
if you can get into setting thru the cluster try:Settings > System > Restart in Safe Mode

 

[MrScrewzloose]

If you pulled the tcm fuse with the battery connected that might explain the tcm error
I would try disconnecting the battery again, but this time leave it disconnected for at least 10 minutes (go 20) to be sure
maybe while the battery is disconnected check the radio harness's in the drivers left rear compartment area where the jack storage is, see if anything came loose or is not correctly seated.
if still nothing, then maybe try hitting the google speech button if you have one on your steering wheel
if you can get into setting thru the cluster try:Settings > System > Restart in Safe Mode

Unfortunately, no success.

As for the safe mode; you can't get into that feature without having access to the UI. My infotainment system is dead, no power, no response.

 

[Wiesem4]

I am going through the exact same issue with my 21 Tahoe Premier. Did you have any luck solving the problem?

 

[MrScrewzloose]

I am going through the exact same issue with my 21 Tahoe Premier. Did you have any luck solving the problem?

Diffidently time to update this thread.

The issues I was dealing with before, e.g. error codes, infotainment system no longer functional, etc. remained the same. It took almost 1 1/2 months to get into my local dealer, and then the truck sat at the dealer for another week before even being diagnosed but that's another story...

The entire problem was due to the failure of the Radio Control Module Part # 87836477, also called the radio receiver. According to the Chevy shop Foreman, this module controls numerous functions within the truck and when it fails will cause a series of communication failures.

Either way, receiver was replaced. I drove off lot and the infotainment system began rebooting, every few minutes. Sometime the reboot would occur every few minutes, sometimes it would go into a boot loop.

Here's a video I took >>

I turned around, right back to the dealer, and the foreman took a look and said radio control module, that was just replaced, would need to be replaced again. This occurred during the holidays so I had to wait another few weeks for the module to come in and get it replaced again. The system has been replaced and is functioning as normal. Crossing fingers.

I've never purchased an extended warranty except with this truck, I did so in case the lifter issue occurred. Thankfully I did as this would of cost $1143.90.

#87836477 Receiver = $752
Labor (2.3 hrs) = $391

According to my Service Advisor, he'd only been there for about 5 months and has already replaced 3x of these units. I hope this helps someone.