Transfer case & parking brake issues

[Eusibius2]

I'm stumped on this one, and could use a little 'online support' to help make some sense out of this. Short story:

1. 2022 Z71 6.2L, 10k miles. Had it for 13 months with Zero issues
2. Heated Steering Wheel retrofit is finally available
3. few weeks ago, could not shift into 4WD HI (pic attached).

Brought it in to dealership to look at 4WD, and also to add steering wheel retrofit. When I was notified everything was done (2hrs), they said they could not find anything wrong with the 4WD and said I'm good to go, sign here. I refused to sign until I checked the 4WD myself. They insisted no error was found, and couldn't replicate it but not being able to shift into 4WD HI was spot on consistent and never deviated. I took the pic attached in the dealer service bay even so I know it was still an issue.

When I checked for myself, here's where things got interesting:

Now, the Parking Brake is always ON until you step on the gas. Shift into any gear, it automatically goes ON. Flat surface, in the service bay. The Service Manager, me and my wife could hear the caliper engaging/disengaging.

I could shift into 4WD HI, Auto, and 2WD, but 4WD LO is not possible at all now. No error on the DIC either. The SVC Mgr tried, too. Couldn't get any different results. He said to just take it home, and he'll do some research on it over the weekend. I said, NO - how about you keep it, give me a loaner, and we talk on Monday? He agreed.

I was able to get them to make copies of the DTC Scans. One is when I entered the shop, and 2nd one is when they said "I'm good to go". Ironically or not, there were more errors on the 2nd one. I wasn't able to read through them until I got home, but it's odd to me that there's so many issues with the VIN# not being programmed, and that there are so many 'lost communication' errors. I asked him to unplug the battery, wait, and then connect it again. Give it the ol' reboot method. He didn't want to and after milling about he said NO, he'll call GM to get some diagnostics and figure out what's going on with the software before he tries that. So I limped home in a loaner Equinox.

Any thoughts from the interwebs what could be going on? Could I have asked better questions, or done something different? Happy to hear opinions... will update when I hear more too.

 

[WalleyeMikeIII]

Suggest to the service manager that if the technicians at his dealership cannot fix these issues, they should tow the vehicle to another qualified GM dealer and get it repaired. Also ask that the district GM service rep look at it. Good lord

 

[Fless]

You guys should talk to each other:

Check Engine Going On/Off

All week my checking engine light has been coming on and off. And of course when Im heading to the dealer, the light goes off. Any of these codes I should be worried about?

www.tahoeyukonforum.com

 

[66 Galaxie]

It could be as simple as a bad plug or disconnected plug in the wiring harness.

 

[swathdiver]

I'm stumped on this one, and could use a little 'online support' to help make some sense out of this. Short story:

1. 2022 Z71 6.2L, 10k miles. Had it for 13 months with Zero issues
2. Heated Steering Wheel retrofit is finally available
3. few weeks ago, could not shift into 4WD HI (pic attached).

Brought it in to dealership to look at 4WD, and also to add steering wheel retrofit. When I was notified everything was done (2hrs), they said they could not find anything wrong with the 4WD and said I'm good to go, sign here. I refused to sign until I checked the 4WD myself. They insisted no error was found, and couldn't replicate it but not being able to shift into 4WD HI was spot on consistent and never deviated. I took the pic attached in the dealer service bay even so I know it was still an issue.

When I checked for myself, here's where things got interesting:

Now, the Parking Brake is always ON until you step on the gas. Shift into any gear, it automatically goes ON. Flat surface, in the service bay. The Service Manager, me and my wife could hear the caliper engaging/disengaging.

I could shift into 4WD HI, Auto, and 2WD, but 4WD LO is not possible at all now. No error on the DIC either. The SVC Mgr tried, too. Couldn't get any different results. He said to just take it home, and he'll do some research on it over the weekend. I said, NO - how about you keep it, give me a loaner, and we talk on Monday? He agreed.

I was able to get them to make copies of the DTC Scans. One is when I entered the shop, and 2nd one is when they said "I'm good to go". Ironically or not, there were more errors on the 2nd one. I wasn't able to read through them until I got home, but it's odd to me that there's so many issues with the VIN# not being programmed, and that there are so many 'lost communication' errors. I asked him to unplug the battery, wait, and then connect it again. Give it the ol' reboot method. He didn't want to and after milling about he said NO, he'll call GM to get some diagnostics and figure out what's going on with the software before he tries that. So I limped home in a loaner Equinox.

Any thoughts from the interwebs what could be going on? Could I have asked better questions, or done something different? Happy to hear opinions... will update when I hear more too.

Communication issues are usually because the battery got too low on juice.

Whenever I had a difficult problem to diagnose, I went around back to the service bays and found the guy with the biggest tool box (the most experienced) and had them work on my vehicle. Of course the folks up front don't like that but I want the most experienced guy for the task at hand to solve my problem.

 

[Eusibius2]

Followup: Got it back this week, and everything seems to be fixed. Here's what happened:

Svc Mgr said he never saw the same issue before, and needed to check with "GM Engineers". He also called a few other dealers in the area, and they haven't had the same issue either. GM had them do a ground fault check, loose wires, that sort of thing. They ended up with 2 solutions:

1 - there were 2 loose pins in the connector to the transfer case (maybe for the sensor? he didn't specify). Adjusted, tightened these 2 pins. @66 Galaxie had the closest fix
2 - low voltage from the battery. He replaced the battery. This one stumped me - I didn't think the battery was low on charge, esp only 1 yr old. But, new battery. OK.

He also said the 2 faulty pins were triggering the Parking Brake to engage, and GM confirmed this was by design. So once the pins were fixed, the Park Brake didn't engage again.

No charge for any of this. Got the heated steering wheel installed, too, which is nice and the last of my "retrofit items". Brought in Friday, picked up Wednesday night. Longer than I wanted, but I'm glad it wasn't longer.

Thanks everyone.