Electrical Issues?

[grzybotheclown]

Hello!

I have a 2018 tourx and today while on the way to work a flurry of service lights came on. Service Stabilitrak. Service all wheel drive. Service advanced frontal lighting. Service power steering. No all wheel drive. But the car itself ran absolutely normal.

There was no loss of power. No check engine light. Never felt like it went to just FWD. Steering remained normal. Headlights worked normal. The only other weird thing was that when I tried to put into manual mode, it did not recognize that I switched it.

I did go ahead and change the battery this afternoon as I was hoping it would solve the issues and it has 63k miles on the original battery. But it did not as the entire way home from all of the pop ups kept happening.

Any idea what it could be? I am letting it sit overnight and maybe that will help sort it out but I'm doubting it. Is there anything else I could do before I have to take into a dealer? There just isn't one that close to me. Thanks in advance for the advice and it is much appreciated.

 

[grzybotheclown]

Update. Went out this morning to go to work and now the car won't start. Everything will turn on and all of the service lights cycle through but it will not even turn over. Getting it towed to the dealer most likely tomorrow. Will see what they end up saying.

 

[Fast Track]

Hello!

I have a 2018 tourx and today while on the way to work a flurry of service lights came on. Service Stabilitrak. Service all wheel drive. Service advanced frontal lighting. Service power steering. No all wheel drive. But the car itself ran absolutely normal.

There was no loss of power. No check engine light. Never felt like it went to just FWD. Steering remained normal. Headlights worked normal. The only other weird thing was that when I tried to put into manual mode, it did not recognize that I switched it.

I did go ahead and change the battery this afternoon as I was hoping it would solve the issues and it has 63k miles on the original battery. But it did not as the entire way home from all of the pop ups kept happening.

Any idea what it could be? I am letting it sit overnight and maybe that will help sort it out but I'm doubting it. Is there anything else I could do before I have to take into a dealer? There just isn't one that close to me. Thanks in advance for the advice and it is much appreciated.

I have had a similar problem with my 2018 GS. I disconnected the battery for 30 minutes then reconnected. It cleared the problem and ran normally.

 

[Profasr]

Sounds like a battery issue - get your battery checked.

 

[grzybotheclown]

Sounds like a battery issue - get your battery checked.

I just put a new battery into the car yesterday afternoon hoping that it would resolve the issues and it did not. Because that is what I thought to do first.

 

[grzybotheclown]

Here is another update.

After I had taken to the local shop they had come to the conclusion that it was out of there scope of what they could do and recommended that I take it to a dealer to look at. They told me that as far as they could tell, the cars computers were not talking to each other and that is what was causing all of the service lights. Just a side note, the shop did not charge for any of there time or diagnostics, so shout out to Reis Auto.

Take it to the dealer and drop if off on Friday. I get a call this morning that the body control module (BCM) was faulty and that is why it was flashing all of the warning lights. Told me it was $600 for everything. Then I get a second phone call saying that there were still some problems and they looked through everything again, and now the gateway control module was faulty. An extra $400 or so. The tech says he is 95% sure that this should be the last issue with the car. I am hoping so.

I will update tomorrow when I hopefully am driving my car again.

 

[grzybotheclown]

Final update for everyone.

I get the phone call from the dealer saying that the car is ready to be picked up and everything is working normally again. It ended up not being the BCM but rather just the gateway control module. They found this by replacing the GCM and they were still having problems with it talking to the BCM. They got on the phone with the GM Service Tech line and they recommended putting the original BCM back in as the new one was most likely a bad part from GM.

They put the the old BCM back in the car and everything ran normally. They did a test drive to make sure everything was functioning properly. I only ended up paying for the GCM part, the diagnostic, and labor which brought the total to just north of $600.

I am glad the car is working again and that I can drive and enjoy it. When I first started looking online to see if there was anything that had come across somebody else's way that was similar to this but I didn't find anything. I am hoping that this thread will help other people out if it happens to them. Thanks for reading.

 

[Fast Track]

Final update for everyone.

I get the phone call from the dealer saying that the car is ready to be picked up and everything is working normally again. It ended up not being the BCM but rather just the gateway control module. They found this by replacing the GCM and they were still having problems with it talking to the BCM. They got on the phone with the GM Service Tech line and they recommended putting the original BCM back in as the new one was most likely a bad part from GM.

They put the the old BCM back in the car and everything ran normally. They did a test drive to make sure everything was functioning properly. I only ended up paying for the GCM part, the diagnostic, and labor which brought the total to just north of $600.

I am glad the car is working again and that I can drive and enjoy it. When I first started looking online to see if there was anything that had come across somebody else's way that was similar to this but I didn't find anything. I am hoping that this thread will help other people out if it happens to them. Thanks for reading.

I appreciate you letting us know the outcome. It's good information that will help someone else down the road.

 

[Lugen]

Final update for everyone.

I get the phone call from the dealer saying that the car is ready to be picked up and everything is working normally again. It ended up not being the BCM but rather just the gateway control module. They found this by replacing the GCM and they were still having problems with it talking to the BCM. They got on the phone with the GM Service Tech line and they recommended putting the original BCM back in as the new one was most likely a bad part from GM.

They put the the old BCM back in the car and everything ran normally. They did a test drive to make sure everything was functioning properly. I only ended up paying for the GCM part, the diagnostic, and labor which brought the total to just north of $600.

I am glad the car is working again and that I can drive and enjoy it. When I first started looking online to see if there was anything that had come across somebody else's way that was similar to this but I didn't find anything. I am hoping that this thread will help other people out if it happens to them. Thanks for reading.

Hi, Original owner of 2018 TourX. Do you know if the GCM needs to be programmed after installation? Or can it just be installed and ready to go? Your description of symptoms is exactly what I am experiencing today. I had a similar issue 2 years ago and had the BCM replaced. Symptoms were a little different then. I’m thinking maybe this time it’s my GCM. Thanks

 

[Undercover87T]

Final update for everyone.

I get the phone call from the dealer saying that the car is ready to be picked up and everything is working normally again. It ended up not being the BCM but rather just the gateway control module. They found this by replacing the GCM and they were still having problems with it talking to the BCM. They got on the phone with the GM Service Tech line and they recommended putting the original BCM back in as the new one was most likely a bad part from GM.

They put the the old BCM back in the car and everything ran normally. They did a test drive to make sure everything was functioning properly. I only ended up paying for the GCM part, the diagnostic, and labor which brought the total to just north of $600.

I am glad the car is working again and that I can drive and enjoy it. When I first started looking online to see if there was anything that had come across somebody else's way that was similar to this but I didn't find anything. I am hoping that this thread will help other people out if it happens to them. Thanks for reading.

Bringing this thread back as something similar happened to my 2018 GS recently and want to add my experience. I've owned the car just over a year, currently around 65500 miles with no prior issues.

A couple days before Thanksgiving I was driving to a store a couple miles away and on two separate occasions the fuel and volt gauges dropped to zero and got the "low fuel" and "AWD off" messages, and both times all returned to normal a second or two later. The following morning the car would not start. I checked the battery with a volt meter and was only getting about 10 volts and discovered it was the original from 2018. Replaced it with and equivalent Diehard Platinum AGM and the car started, but had multiple error messages similar to what was described in the original post here, plus P0700, U0100, & U0101 codes for loss of communication between ECM and TCM. The car also displayed the "shift to park" error so the ignition would not shut off, the e-brake would not release and the rear hatch would not open. I was able to crawl through the back seat and disconnect the battery. After about 10 minutes I reconnected the battery and the car was able to start and release the e-brake so it could be towed.

Had the car towed to the local Chevy dealer who I'd delt with in the past. They called about two days later and said yes we confirmed the issues you described we're looking into it and will call you back with an update. A little over two weeks goes by and I called for an update. Service manager stated the only thing they were able to find was a loose pin in the connector for the serial gateway module (GCM) causing an intermittent loss of communication between other modules. They repined the connector, added dielectric grease, and put about 50 miles on the car without any issues. I've put another 100 miles on it since getting it back last weekend and all is well so far.

 

[thesyguy]

Here is my recent electrical issue with by 2018 TourX Essence. Driving home all of a sudden the ABS, Stabilitrak, and AWD lights come on. I also lost lane keeping, parking sensors, and adaptive cruise. Pulled codes and found U0420-71, U0414-71, U0415-00, U0415-71, C0040-67, C0040-06, C0041-29. Basically the right front ABS sensor was not sending signal and all of the other systems cannot operate without the data from that sensor.

Weekend 1 - replace right front ABS sensor ($25), no joy. Problem still exists. Found a GM TSB online saying that the error can be caused by a bad magnetic ring in the wheel bearing and the bearing should be replaced.

Weekend 2 - Replaced the wheel bearing ($68). No joy. Problem still exists.

Weekend 3 - At this point it had to be either wiring or the ABS/brake control module may be bad. Decided the next step was to trace the wiring harness from the right front ABS sensor to the control module to see if there was any issue before I started down the road of the module replacement which requires programming that I cannot do. After an hour I found a spot where the wiring harness was touching the AC line on the passenger side of the radiator. It comes up the radiator support and then runs over to the firewall. It was worn through and wiring was exposed.

Weekend 4 - In order to get that harness up and out for repair it requires disconnecting all of the connections down below, mainly the ABS sensor and everything in the front bumper cover which is conveniently routed to a single connector just above the right front frame rail. To get to these connectors you must remove the inner fender liner, all of the plastic and steel covers under the engine/bumper, and removal of the front bumper cover. Then the harness can be unclipped from the frame/radiator support and pulled up. There was one wire going to the ABS sensor that wore right through. Repaired the wire, re-wrapped the harness, and reinstalled all of the removed parts. Cleared the codes and viola, issue resolved.

Fortunately for me, I have access to a shop with a lift so I was able to do weekend 4 much easier. Plus I have been working on vehicles since I was thirteen years old. If this had been done by a dealer, the cost would have been in the thousands. For me the only real cost was the sensor and bearing that I did not need to replace.

For some reason, Buick did not properly separate the wiring harness from the AC line and actually wrapped the harness around the line as it came up the radiator support despite there being plenty of clips holding the harness in place. No idea why anyone would do anything so stupid. I rerouted the harness so it can no longer rub against anything.

 

[GeorgeG]

Wow I'm impressed! That is a lot of work. So the question is can that area be reached without taking the car apart?

 

[thesyguy]

Wow I'm impressed! That is a lot of work. So the question is can that area be reached without taking the car apart?

Unless you have three foot arms with infant hands, no, you have to disassemble the front end to access the mounting points of the harness on the frame and radiator support. Otherwise there is not enough slack to pull the harness up to where you can work on it.

 

[thesyguy]

Anyone with a 2018-2020 Regal, any model, should check to see if your harness is rubbing against the AC line. If it is, I recommend wrapping the AC line with a 3-4” piece of 3/8” ID rubber hose sliced straight down the length of the hose and secure with zip ties. This will prevent damage to both as now I am pretty sure this is the issue with my AC system needing additional R1234-YF Freon every spring. There is probably a pin hole in the line. I will check in the spring with a sniffer. Hopefully this is not the issue as that AC line is no longer available. If so, I will have a custom one made but am sure it will be at least twice the original price.