GM BCM Problems

Craig Technical Support Specialist Chicago, Illinois Posted   Latest   Edited  
Case Study
2006 Chevrolet Express 1500 4.3L (X LU3) 4-spd (4L60-E)
Security Theft / No Start

Commercial delivery van with a bad habit of stranding the driver after a hot soak restart. vehicle has been to several shops with the last facility replacing "everything in the column". Driver of the vehicle states when problem occurs theft light flashes, vehicle is a no start until it cools down. Owner of the vehicle has had a lot of strange issues with the vehicle for years, problems with lights, chimes, and the starting issue being the most recent.

Digging online I found lots of posts with issues relating to the BCM, including people having issues with OEM parts from the dealer. Many of the posts mention heat as being a large factor in diagnosing the BCM. 

BCM was pulled from the dash and the clam shell removed, a detailed examination of the board revealed a multitude of cold soldered poorly filled connections all on the header pins exiting the case.

OK lets desolder, clean, flux and resolder. Repeat 42 times and were done. Vehicle returned to the customer over the holiday week and has reported no issues so far. 

Hopefully the information will help someone fix one of these or at least provide something to check when the BCM is suspect.


Gail Technician
Garner, North Carolina
Gail Default

Are these a one & done on programming? Great that it didn't lose it's "memory". Appreciate the repair vs replace. Any way to route some air flow to these? Maybe tap in a small hose to HVAC box since most GM run the blower on low speed at all times.

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Craig Technical Support Specialist
Chicago, Illinois
Craig Default

Gail, I am not sure of this modules ability to be reprogrammed or it's programmed memory volatility, thanks for bringing it up though. I honestly wasn't to worried about harming anything in the module as I was only dealing with connector pins, no components were touched. I suspect one could attach a fresh air hose to the plastic case and the blower box, my only concern with that would be blowing…

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Craig Owner
Rowland Heights, California
Craig Default

Just had this vehicle in with same issue and resolve. 2014 Chevy Cruze. Poor Solder Joints as well. My cost on the BCM was 178 Bananas. More cost effective for me to replace vs. repair as I give a 2 year warranty. I do applaud your repair though and I did so that many times on the Bosch units on the Maserati/Porche applications when I was younger.

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Josh Diagnostician
Jacksonville, Florida
Josh Default

I have had this problem in the past and just a week ago on a friend of mine on his 04. These have had an issue with the wiring harness behind the dash (instrumen cluster), wrapped in conduit as well as the harness for the cigarette lighter. I’ll attach a picture, there is a TSB out there for it but i have seen the issue and it not be listed for the particular vehicle. I have seen and had to do…

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Craig Technical Support Specialist
Chicago, Illinois
Craig Default

Josh, thanks for the information, I will have to remember to inspect the dash wiring on these vehicles when dealing with odd problems. Craig

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George Owner/Technician
Skagway, Alaska
George Default

What ever happened to quality control. I saw this a lot on the cheap overseas radiators as well. I wonder were these are being made? Oversees probably.........

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Craig Technical Support Specialist
Chicago, Illinois
Craig Default

George, I don't know where GM gets it's modules from, definitely could be a sourcing problem, but I very much suspect a lot of the MY 2000 and onwards vehicles to have lots of soldering issues in multiple modules. I believe this trouble started as lead was removed from the solder being used and more components being changed from through hole design to today's SMD (surface mounted device) style…

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Michael Mobile Technician
Clinton, Utah
Michael Default

Craig, Fantastic work! Thanks for sharing!

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Matt Educator
North Canton, Ohio
Matt Default

Good catch and nice job on the repair. When I first started reading it reminded me of problems with intermittent no-start and security light on GM trucks. The problem was usually the connector at the base of the column (C201) I think. Loose pin fit and would only act up when the column was tilted up and it pulled on the harness. I'm going to remember the BCM problem you found and look at solder…

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Danny Instructor
Montréal, Quebec
Danny Default

The worse wiring job I have seen was the Sunfire. Front lighting ckt Connections done with a press with duct tape as a insulator. We started to do repairs on the PDI.

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Tim Mechanic
Blytheville, Arkansas
Tim Default

Great catch Craig! Thank you so much for sharing. I will look at this as a possibility next time I deal with one of these.

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