NEED HELP 2005 Buick Rainier Intermittent Electrical Issues

[USCGCWO]

I have a 2005 Rainier, 4.2L inline 6 with @125,000 miles and I’m about ready to junk it. Intermittent electrical issues are a real PITA. I have been trying to get these issues corrected literally for months. I believe they are all due to one thing but I can’t find “the thing” and I’m hoping someone here can help me solve the issue(s). Here we go with the issues:

1. Fuel gauge mostly inop. I think that’s just a bad sending unit but putting in the list just in case.
2. Lift gate latch continuously locks/unlocks when the gate is open.
3. Rear wiper inop.
4. Intermittent failure to recognize the fob, door locks work with door button.
5. The biggie, the dash warning lights for ABS and Brakes, dual lights for parking brake engaged and brake system failure. This is the one that really needs to be repaired as I need to have the car inspected for license renewal.
6. Codes are :
   C0265 ABS SOLENOID CONTROL MONITOR ERROR
   P0463 fuel level sensor circuit high voltage
   U1000, U1064, U1161 Driver seat module
   U1166 loss of communications

What I have done:

1. Replaced rear wiper motor. I now have a used but good wiper motor.
2. Replaced BCM, did not correct all issues but did correct an issue with the SRS.
3. Found and repaired 4 broken wires where they exit the body and enter the lift gate.
4. Replaced batt in fob, threw away a good batt.
5. Stretched out the leads on my Fluke meter to ring out the wires from tailgate to BCM.
6. Upgraded my OBD reader to an Innova 3170rs. Clears codes and looks cool.
7. Unplugged the splice pack under RR seat, forget the number, test drove and returned with no joy.
8. Just did a scan, active codes are C0265, U1000, P0463.

So what do ya’ll think? I just saw on a forum thread that the fob goes through the lift gate module and I don’t want to prime the pump but, does this look like a module issue or a broken wire issue?

 

[USCGCWO]

Forgot to add that the Innova could not establish comms with the lift gate module.

 

[TollKeeper]

I would start by checking the ground for the liftgate. If I am remembering correctly, its on the inside, just in front of the drivers taillight.

@Mooseman I think might know more about that

If that doesnt work, the next step would be to completely disconnect the TGM (tail gate module). When you do this, make sure you do NOT put the tail gate back together, as there will be no electronics to open any electronic buttons. So once you close the tail gate, you might need the coverings to not be in the way to re-open the tail gate. And test everything out not including whats in the tailgate.

I know the seal that goes around the exterior handle goes bad, and moisture getting in there can do all types of bad things to electronics.

 

[Mooseman]

I think your EBCM has failed and possibly causing the U1000 code, killing the network, along with the C0265. I would first confirm that the wiring is good to the EBCM first before condemning it. Once unplugged, the U1000 should clear and stay off if the EBCM is killing the network. Another possibility is a bad ground for the EBCM and the fuel level sender.

The EBCM has been known to go bad with bad solder joints and water intrusion.

 

[mrrsm]

Following on with Class 2 Network issues where any one of the many Modules can cause system wide communication issues between Modules, the PCM and BCM,,, the issues with intermittent comms can focus in on the LGM Wiring becoming Work Hardened and have failures as the Harness Wires break.

Thus, Key Fob Issues and Lock-Unlock phenomena will develop, These can be completely independent issues between the EBCM Problem...and the Lift Gate Events, yet all be converging as network communication problems as UXXXXX Error Codes.

For example, the Harness Wiring passing through the upper rear roof through to the Lift Gate can be the cause and origin of the Lift Gate and Wiper Motor Issues,

These images show where to look, with the added idea that the wires can be broken inside of intact wire insulation that can be examined via a Continuity Check once the many Connectors on the LGM are disconnected and probed with a DMM after investigating the Wire Harness items and functions as well as colors via the Class 2 Network and Powers-Grounds ID'd from a Wiring Diagram.

The actual Broken and Separated Wires will become obvious once the Grommet area near the roof line is opened and inspected:



PS: Nice to see a USCG CWO as a GMT Nation Member... from a Veteran USCG Enlisted Aviation Machinist's Mate.

 

[Mooseman]

Even though you repaired the wires in the liftgate, you might have missed one that's deeper in the body or liftgate. I'd recheck them by tugging on each both ways.

 

[USCGCWO]

Even though you repaired the wires in the liftgate, you might have missed one that's deeper in the body or liftgate. I'd recheck them by tugging on each both ways.

I think you are correct as the ABS &brake warning lights will be off for miles then all of a sudden come on. Other times they come on right after I start the car. An unusual thing is in cold wx the lights seems to stay off longer. I find that odd and do not know what to think of that. I'm a diesel mechanic by trade, as a sailor I worked on anything mechanical on a ship and never seen something like that.

 

[USCGCWO]

Following on with Class 2 Network issues where any one of the many Modules can cause system wide communication issues between Modules, the PCM and BCM,,, the issues with intermittent comms can focus in on the LGM Wiring becoming Work Hardened and have failures as the Harness Wires break.

Thus, Key Fob Issues and Lock-Unlock phenomena will develop, These can be completely independent issues between the EBCM Problem...and the Lift Gate Events, yet all be converging as network communication problems as UXXXXX Error Codes.

For example, the Harness Wiring passing through the upper rear roof through to the Lift Gate can be the cause and origin of the Lift Gate and Wiper Motor Issues,

These images show where to look, with the added idea that the wires can be broken inside of intact wire insulation that can be examined via a Continuity Check once the many Connectors on the LGM are disconnected and probed with a DMM after investigating the Wire Harness items and functions as well as colors via the Class 2 Network and Powers-Grounds ID'd from a Wiring Diagram.

The actual Broken and Separated Wires will become obvious once the Grommet area near the roof line is opened and inspected:

View attachment 118783View attachment 118784View attachment 118785

PS: Nice to see a USCG CWO as a GMT Nation Member... from a Veteran USCG Enlisted Aviation Machinist's Mate.

The photos of the broken wires is exactly what I had and repaired. And just had a thought, I need to do the wiggle test as @Mooseman suggested but on the wires I already repaired also.


Hey Coastie! Not too many of us around on forums. I see you have Tampa area as your home, were you at Clearwater? I was an MK then Naval Eng. I actually retired as LT but CWO4 pay is higher than O3E pay by about 50 bucks so due to the save pay act they pay me as CWO. Whatever, right?
If you were at Clearwater in '94 you guys helped me out with a logistics problem.

 

[USCGCWO]

I would start by checking the ground for the liftgate. If I am remembering correctly, its on the inside, just in front of the drivers taillight.

@Mooseman I think might know more about that

If that doesnt work, the next step would be to completely disconnect the TGM (tail gate module). When you do this, make sure you do NOT put the tail gate back together, as there will be no electronics to open any electronic buttons. So once you close the tail gate, you might need the coverings to not be in the way to re-open the tail gate. And test everything out not including whats in the tailgate.

I know the seal that goes around the exterior handle goes bad, and moisture getting in there can do all types of bad things to electronics.

There is no moisture in the tailgate, everything is dry as a bone. In post 1 I listed the things I did. Item #7 was disconnect the splice pack, would that not disconnect the TGM? I did a scan with it disconnected and the scanner could not find the TGM so I think it was. Thoughts?

 

[Mooseman]

Item #7 was disconnect the splice pack, would that not disconnect the TGM?

That was just the rear one which is a split off from the main one under the left side dash and has just a few modules connected to it, including the LGM (Lift Gate Module). I don't think the LGM is your problem as you are getting that error with the EBCM.

The main splice pack will cut off everything, including the rear splice pack. You should pull the comb in that one, jumper just the EBCM and OBD port, see if you can communicate with it and get error codes. I would also jumper in the BCM and PCM into the mix to see if the U1000 and/or EBCM codes comes back.

Go to Charm.li and get a copy of the data communication lines to know which wires at the splice pack go to which modules.

 

[TJBaker57]

That was just the rear one which is a split off from the main one under the left side dash and has just a few modules connected to it,

LGM Liftgate Module
DDM Drivers Door Module
FPDM Front Passenger Door Module
VCIM Vehicle Communications Module (if equipped)

SP300 - SP399 — 2005 Buick Rainier AWD L6-4.2L VIN S Service Manual | Operation CHARM

Detailed repair manual for the 2005 Buick Rainier AWD L6-4.2L VIN S.

charm.li

 

[TJBaker57]

Just did a scan, active codes are C0265, U1000, P0463

As far as the ABS and Brake warning light the C0265 would be the first DTC to be addressed. That DTC is independent of serial data, it looks to be saying there is an issue with the power or ground to the ABS motor.

C0265 — 2005 Buick Rainier AWD L6-4.2L VIN S Service Manual | Operation CHARM

Detailed repair manual for the 2005 Buick Rainier AWD L6-4.2L VIN S.

charm.li

 

[USCGCWO]

Thank you all for the replies and suggestions. Life has a way of interfering with your plans, finally getting back to troubleshooting. I will keep everyone posted on progress or lack thereof.

 

[USCGCWO]

Started back troubleshooting and something odd happened. I had the lift gate open and was checking a number of things, grounds mostly, and took the panel off to access the splice pack under the dash.
Went inside for a head call (bathroom for you land lubbers) and when I came out the lift gate lock was cycling lock/unlock. It had not done that for the 3-4 hours I had been working, quiet as a mouse. The only thing different between starting work and now is I did wiggle wiring under dash.
Getting dark here and need to do chores, I will get under the dash tomorrow, any thoughts on where to start?
ETA: None of the doors have ever cycled the locks like the tail gate. Thought that may be useful info.

 

[mrrsm]

...and here is a *.PDF of @TJBaker57 's Charm C0265 Diagnostic Flow Chart Find in Post #12:

 

[Mooseman]

ETA: None of the doors have ever cycled the locks like the tail gate. Thought that may be useful info.

When the tailgate cycles, do the interior lights also go on/off? I'm thinking the switch that senses the tailgate is open or closed is malfunctioning. When you open the tailgate, it's supposed to lock the glass hatch. If the switch is intermittently working when the tailgate is open, it could do that lock/unlock of the glass hatch.

 

[USCGCWO]

When the tailgate cycles, do the interior lights also go on/off? I'm thinking the switch that senses the tailgate is open or closed is malfunctioning. When you open the tailgate, it's supposed to lock the glass hatch. If the switch is intermittently working when the tailgate is open, it could do that lock/unlock of the glass hatch.

No, the interior lights do not cycle too. I don't know if the glass latch is cycling but I know for a fact the lift gate latch does as I have the moulding pulled and I unplug the gate latch and it quits.

Just finished going through all the grounds, they're all clean now but test drive was no bueno. Back to troubleshooting.

 

[mrrsm]

I've plugged your 2005 Buick Ranier LL8 4.2L SUV into my Snap-On Vantage-Pro Diagnostic Tool to retrieve all of the "Guided Power Door Locks Component Tests" and then memorialized these extensive, discrete digital images that covers (1) The Component Operational Data (2) The Component Location Specifics (3) the Electrical Component Connectors and their Pin-Outs and (4) The Diagnostic Procedures and what the Technician should expect as Nominal Volts and Resistance Results when using a DMM.

These Digital Screen Images are more numerous and informative than you might think... but I would rather ask your permission prior to posting them here as consecutive Step By Step Images in Groups of 20 in follow on Posts, rather than clutter up your Thread with any unwanted assistance. Please let me know...

 

[USCGCWO]

I've plugged your 2005 Buick Ranier LL8 4.2L SUV into my Snap-On Vantage-Pro Diagnostic Tool to retrieve all of the "Guided Door Locks Component Tests" and then memorialized these extensive, discrete digital images that covers (1) The Component Operational Data (2) The Component Location Specifics and (3) the Electrical Diagnostic Procedures and what the Technician should expect as Nominal Results when using a DMM.

These Digital Screen Images are more numerous and informative than you might think... but I would rather ask your permission prior to posting them here as consecutive Step By Step Images in Groups of 20 in follow on Posts, rather than clutter up your Thread with any unwanted assistance. Please let me know...

Go for it! Please!

 

[mrrsm]

Okay... This is going to take a while... there are 90 Consecutive Images that cover all aspects of the 2005 Buick Ranier Power Door Locks and they have to be centered, cropped, sized and then re-sized using the Linux Mint Photo App called "Gwenview".

As each Block of 20 are ready for posting...I'll drop them here for you in their respective order. Sort these Numerically after you Download them to peruse and use Off Line. You won't be disappointed:

First Batch of 20 Images:




More to Follow On as the Editing gets completed...

 

[mrrsm]

Second Batch of 20 Images:



More to Follow...

 

[mrrsm]

Next Batch of 20 Images...



More to Follow On...

 

[mrrsm]

Next to the Last: Batch of 20 Images...



Last Batch Follows...

 

[mrrsm]

Last Batch of 10 Images...Total = 90 Images:

 

[USCGCWO]

Wow @mrrsm that's a lot of work, thank you so much. Got homework to do now.

 

[USCGCWO]

Well good news on the ABS C0265 issue. It's fixed! Doing more research I found this a Chevy site, not sure of the forum rules so I won't link unless given the OK by a mod. This photo does show the problem, re-soldered the pin and that corrected that problem.
While that issue is corrected I still need to go through the all the wiring to find the issue with the tailgate lock cycling.

 

[Mooseman]

Nice! No problem linking to other forums. In fact we encourage it so that we're not accused of plagiarism (and it's in the rules).