2017 Lacrosse Premium - Electrical Hiccups

[FelixUnger]

Thanks in advance for anyone who comments.

2017 Buick Lacrosse with 28,000 miles. I love this car. It's great looking and rides like a dream. About a month ago, i was driving and I get a "service transmission" and "service stabilitrack" alert on the DIC. Felt a minor lurch, but nothing major. Check engine light came on but I was able to drive on. I took it to a local GM dealer. They tested the connections, got a couple codes, ended up replacing the battery because they said the CCAs were low and the battery is often the cause of random alerts like this.

A couple days later, pulling out of the driveway and I get a series of DIC alerts. Transmission, stabilitrack, power steering, brake assist, etc. Car shuts off, sounds like the brakes engage, lights inside stay on. I put it in park. Turn off, turn back on and it starts like nothing is wrong. Check engine light is on. Take it to the dealer, they can't recreate the issue.

few days later, same as above. I drop it off at the dealer. They get a sheet of codes, can't pinpoint exactly which one it is. Quote the tech, "I can't see how this car is actually running". Basically, i'm told all the modules and computers talk to each other and it becomes difficult to pinpoint the exact one causing the issues.

A couple days later... driving down a back country road. Transmission, stabilitrack, power steering, brake assist, etc. Car shuts off, sounds like the brakes engage, lights inside stay on. I put it in park. Starts back up after 30 seconds. Same trip - pull into a parking space a few miles down the road, car dies. Get all the previous alerts plus articulating headlight issue. Will not restart. Pushing power just gets me the instrument cluster, flashing lights on gear shifter. Car takes a ride on a AAA flatbed back to the dealer. When unloading the car, tow truck driver tells me to put it in neutral to get it off the flatbed, car starts. Dealer reviews. Sheet of codes. Dealer isolates and replaces a transmission module. (can't remember exactly which one)

About a week later, haven't driven it much. Same country road - same spot in fact, car shuts off and i get the same couple alerts. I get it to restart. I get where i'm going, park. Coming out about 45 minutes later, remote start will not start. Car starts with push button. Go 1 mile, i get a brake alert but it goes away. Pull into gas station. Fill up. Car will not start. Only get dash lights, DIC is throwing off about 10 alerts. Transmission, stabilitrack, power steering, brake assist, articulating headlamps, and a couple others. Car takes another trip on a flat bed. This time the parking brake engages itself and won't release, but i do get it into neutral. Car does not start this time coming off the flat bed.

I feel like I've had one or two similar instances of the car shutting off, but you get the point. The dealer has had it for about a week now. I called yesterday and the guy says they're working on it. Tells me "it occasionally starts, other times not. Articulating headlights were moving on their own. (Should I name it Christine?) Dash went black at one point. Tech is still working on it."

1) Anyone ever experience anything like this and have suggestions that I could take to the dealer? I've seen a few similar posts that recommend the grounding cable. I'm assuming this would have been checked when they replaced the battery.
2) Once they do fix it, am I crazy to keep the car? I don't trust that they've actually fixed it or that it will stay fixed. I'm seriously thinking of taking it 30 miles down the road to the nearest Buick dealer that has any inventory and trading it in on a new Enclave Avenir.

Thanks again for any insight which you can offer.

 

[MelsRegal]

Have they checked for technical service bulletins?
Have they or you called GM?
Is there another dealer nearby?

 

[FelixUnger]

Have they checked for technical service bulletins?
Have they or you called GM?
Is there another dealer nearby?

Thanks Mels -

Yes on the TSBs. I'm calling them tomorrow to see if they have called GM as I'm getting concerned. Closest other GM dealer is about 10 miles and since it doesn't run, I'm not sure I'm ready to move it. The other dealer is more corporate, current dealer is more of a family location.

 

[FelixUnger]

In case anyone is interested or needs this information later... 99% sure it is the body control module, or the connectors to it. Still trying to break it again because it's under the extended warranty and they need to prove it.

 

[richardnewton]

We had a 2013 with less severe issues. Cleaned a few grounds near the battery. Search my posts for ideas.

 

[G-517315]

Have 2017 Premium with same issues. Bought it in June 2022 with 16k miles. Problem first appeared around 25k. Been to the dealer 4 times and they can never find the root cause. Had it at dealer in June of 2023 and they said they fixed it (ECM they said), but last week it started again, getting progressively worse/more frequent. Sometimes car won't start or shut off depending.. Any guidance is appreciated.

 

[HotZ28]

Lemon laws applies to these type of issues!

 

[MDC58]

Have 2017 Premium with same issues. Bought it in June 2022 with 16k miles. Problem first appeared around 25k. Been to the dealer 4 times and they can never find the root cause. Had it at dealer in June of 2023 and they said they fixed it (ECM they said), but last week it started again, getting progressively worse/more frequent. Sometimes car won't start or shut off depending.. Any guidance is appreciated.

I have a 2017 as well did you ever find out what causing the issues ?

 

[MDC58]

In case anyone is interested or needs this information later... 99% sure it is the body control module, or the connectors to it. Still trying to break it again because it's under the extended warranty and they need to prove it.

Did you ever find out what was causing the issues ? Was it the BCM ? my 2017 Lacrosse Premium has exactly the same symptoms.

 

[PulpFriction]

Coupla things:

1) Multiple electronic wacky behaviors is usually a power problem, most often just a dying battery, or bad alternator, or corroded ground(s), or....
First step, check the voltage at the battery posts. Then plug in to a high-capability scanner and write down all the codes. If the battery is low and old, just replace it. Relatively cheap, and pointless trying to diagnose electrical problems with an iffy battery.

2) ESC light? Turn off the car and restart. Recurrent ESC light? Scan for C codes. Cheap scanners won't read them. Common problem is a sensor circuit. Broken wire, corroded connector... Dirt in the sensor area can even cause problems. Clean them out. I remember a TSB on this. You will be told you need new wheel bearings. Resist until your sure it's really necessary. Some cars have integral sensors, some don't.

 

[MDC58]

I pulled out the BCM, ran the numbers and it is for a Chevy Cruze ! I wonder if this is the cause for my strange electrical issues ?

 

[PulpFriction]

I pulled out the BCM, ran the numbers and it is for a Chevy Cruze ! I wonder if this is the cause for my strange electrical issues ?

I can't see anything in that fuzzy image.

Your car does not throw codes for a Chevy Cruze, it throws codes for your car.

What codes? The numbers, not descriptions.

 

[MDC58]

I can't see anything in that fuzzy image.

Your car does not throw codes for a Chevy Cruze, it throws codes for your car.

What codes? The numbers, not descriptions.

U0420, U0402,U0401,U0140,U0073,U0151,U0073,U0131,U0100,C0161
The part # on the BCM that was installed from the factory is 13514637
As per the earlier post I was reading I completely removed the BCM from the car inspected the connections and reinstalled the BCM, cleared all the code so far everything is working normally, but for how long only time will tell.

 

[MDC58]

In case anyone is interested or needs this information later... 99% sure it is the body control module, or the connectors to it. Still trying to break it again because it's under the extended warranty and they need to prove it.

 

[MDC58]

Update, I bought a brand new BCM from GM and had the local Cadillac dealer program it and updated all the software available for this car everything is working properly now the biggest thing I noticed is the charging voltage is constantly above 14v with the old BCM the voltage would drop down to 11.9 volts and continuously fluctuates I will keep you posted.

 

[PulpFriction]

Update, I bought a brand new BCM from GM and had the local Cadillac dealer program it and updated all the software available for this car everything is working properly now the biggest thing I noticed is the charging voltage is constantly above 14v with the old BCM the voltage would drop down to 11.9 volts and continuously fluctuates I will keep you posted.

Thanks for the update. All those U codes screams low voltage, so no surprise you were seeing 11.9V. Would be nice to know exactly what was going wrong. It sounds like reprograming your original BCM fixed it, but you replaced it anyway. Do I understand that correctly?

 

[MDC58]

Have 2017 Premium with same issues. Bought it in June 2022 with 16k miles. Problem first appeared around 25k. Been to the dealer 4 times and they can never find the root cause. Had it at dealer in June of 2023 and they said they fixed it (ECM they said), but last week it started again, getting progressively worse/more frequent. Sometimes car won't start or shut off depending.. Any guidance is appreciated.

Sounds like the Body Control Module

 

[MDC58]

Thanks for the update. All those U codes screams low voltage, so no surprise you were seeing 11.9V. Would be nice to know exactly what was going wrong. It sounds like reprograming your original BCM fixed it, but you replaced it anyway. Do I understand that correctly?

I installed a brand "New" BCM from GM and the dealer programmed it with all the updated software available for the car, he said all software I was running was out of date.
The biggest thing I noticed is my charging voltage is constantly above 14v and no crazy issues, I will keep you posted.

 

[MDC58]

I installed a brand "New" BCM from GM and the dealer programmed it with all the updated software available for the car, he said all software I was running was out of date.
The biggest thing I noticed is my charging voltage is constantly above 14v and no crazy issues, I will keep you posted.

Update : After 7 days of enjoying 14.3 volts and no issues of any kind I noticed the charge voltage dropped to 13.9 -14.1 still no issues at that point the next day the charge voltage would not go above 13.5 then without warning the voltage took a nose dive to 11.5 and stayed there ! Needless to say all my issues came back (service transmission, service suspension parking brake locked etc...) Is this a indication of a faulty alternator ?

 

[MDC58]

Update : After 7 days of enjoying 14.3 volts and no issues of any kind I noticed the charge voltage dropped to 13.9 -14.1 still no issues at that point the next day the charge voltage would not go above 13.5 then without warning the voltage took a nose dive to 11.5 and stayed there ! Needless to say all my issues came back (service transmission, service suspension parking brake locked etc...) Is this a indication of a faulty alternator ?

In case anyone needs this information, I finally narrowed the issue down to the "serial gateway module" this module acts like a router for the other modules so it plays a big part in communications, I replaced the part myself $57.00 the problem is you have to disassemble a lot of the dash to replace this part it sits behind the radio ! I took the car to the Buick dealership and had it programmed for $99.00 the car has run flawless for a month now I believe this time its fixed for good 👍