'07 Yukon XL Denali w/ Multiple Wiring Issues

[tegimaster]

This is my first post so I apologize if there's an answer for this elsewhere, I've just spent all day trying to resolve my issue and I'm at my wit's end.

Tl;dr at end.

Backstory:
My wife and I bought a 2007 GMC Yukon XL Denali a couple years ago. 151It died in the middle of its test drive which should've been our red flag but the dealer spent 2 weeks "having all the engine sensors replaced" and a 2nd test drive went without issue so we bought it anyways.
Since we started driving it home (4 hr trip) it's intermittently thrown "Service Traction Control/Service Stabilitrak" error codes on the dash. It also randomly throws a "Camshaft Position Sensor" check engine light code, but only when the other Stabilitrak light is active. If the Stabilitrak service light goes out long enough the check engine light goes out too.
I have replaced the entire rear air shock suspension system, cleaned the front engine compartment fuse box, and replaced the throttle position sensor, brake position sensor, brake light sensor, engine-to-frame ground strap, and about half the fuses in the 2 main fuse boxes. I have also replaced the O-Ring for the oil pick-up tube.
While driving I have noticed that the transmission shifts harder when the "Service Traction Control/Stabilitrak" light is on. Primarily it seems to the the 1-2 gear shift, but I am not 100% certain.

Today:
All of the switches on the driver's door quit working while running errands in town. When we got home I looked at the wires in the hinge and noticed the black one had been patched with a solder-less crimp connector and had broken at the edge of that connector.I disconnected the battery, cut the connector out, and soldered the wires together. When I re-connected the battery (it was maybe an hour due to multitasking) the dash errors were still present along with "Door Ajar" as I expected, but also "Park Assist Off."

I thought that was weird so I went to start it and the car wouldn't crank, start, or otherwise respond to my attempts to start. I thought maybe the trunk being open was a culprit but the trunk wouldn't close either.

I got my code reader (Not Tech2) and it said "U0140-00 Lost Communication With Body Control Module" which explains why it won't crank or anything.

I've seen lots of people posting similar issues, but only a few that I really felt was my issue. I suspect that somehow in fixing a wire for my driver's door and/or disconnecting and connecting the battery... I fried my BCM? I see a few who agree that this is a thing that can happen, but did it happen to me?

I traced fuses for the modules in question and replaced them all, removed my BCM, cleaned contacts, and re-connected. I unplugged my battery, touched the cables together, and let it sit for an hour. No change.

Attached are pictures of all error messages on my dash as well as my code reader.

Is it possible that I've missed something in my troubleshooting?

D I have to replace my BCM? If that's the case I'm in for a treat because the closest GM dealer is ~2 hours away and I'm too poor to have the car towed to say the least about dealer fees for that sort of work.

I've seen posts and talk about buying used/aftermarket BCMs and flashing it at home, but I also see people saying that it doesn't work anymore.

TL:dr:

Poor man solders broken wire in driver's door of '07 Yukon XL Denali and fries BCM? Too poor for very distant dealer to fix. Help!

 

[Izusu472]

Look for a 2amp mini fuse in the engine compartment fuse box… That fuse is a ignition fuse and it will cause the truck to not crank… Give me a few minutes and I’ll run over to my truck and tell you what the fuse is called and location…

 

[Izusu472]

Fuse 35 2amp and it’s DLIS

 

[Izusu472]

I also see that you abs and traction control is lit up on the dash… There is a module below your radio/hvac controls inside the dash that controls your OnStar and Bluetooth… there’s going to be 2 harnesses that plug into it… The module will have 4 openings but there are only two plugs that will connect to the module… if the plugs aren’t connected then you can connect them back in and the groves on the connectors will only work with the port it belongs in…

 

[tegimaster]

Thank you with the quick reply and a new idea.

I just replaced that fuse even though it didn't look blown (I have a huge multiplack just for this car). No change though.

Since I was there I ran every other section of my code reader to see if I could get anything different to narrow down this issue. While I was there I noted other oddities.

Every 2nd time I turn the ignition switch on, only the check engine light comes on for the first 5 seconds, then every other light comes on and the car dings.

While the ignition is on I thought I heard a fan blowing, but it was actually the speaker above my head buzzing constantly even with the stereo off.

I also read codes under ABS and SRS:
ABS 1/2: U0140-00 Lost Communication with Body Control Module
ABS 2/2: C0561-71 System Disabled Information Stored - Invalid Data
SRS 1/2: B0081-71 Passenger Presence Module - Invalid Data
SRS 2/2: B0090-71 Rollover Sensor - Invalid Data

The ABS is new with this issue but my traction control light being on has been pretty standard since I got it. Part of my stabilitrak issues. I'll look for that module.

Side note, I don't think I have bluetooth, my onstar is a button on my rear view mirror.

 

[tegimaster]

I don't believe I have the module you are referencing. Looking at the back of my stereo it seems that is where the OnStar plugs into.

Unless the module is further behind my dash? I can attempt to dig further tomorrow. It's too dark now and I've just discovered that all my interior lights are also no longer working.

 

[Izusu472]

Yes sir that’s the module… So by any chance do you have a aftermarket radio or did the last owner have any aftermarket equipment like an alarm ( Besides the OEM keyless entry)… It’s starting to sound like there was aftermarket equipment installed and it wasn’t installed correctly… I have the complete electrical schematics from the OEM from 07-14… If you want I can email it to you… Also I have one last idea for you to try… Have you tried relearning your key??? Ive attached a link to the procedure…GM key programming

 

[tegimaster]

I still have the factory radio/dvd player, which is one of the few things still working.

I did find and remove a GPS tracker that someone wired in next to the OBD2 port. I found it when I took the BCM out to clean. They only tapped into a red wire there, and grounded to the bolt holding the OBD2 in. Removing it didn't change anything.

An OEM schematic never hurts to have.

I'll attempt a key re-learn here shortly and report back.

 

[tegimaster]

I attempted to reprogram my key with 2 different instructions but the car did not respond.

Another discovery: my door locks and rear door windows do not work.