Module Issues

I have a 2015 GMC Savana 3500 cutaway box van.
Experiencing intermittent control module issues. I can drive for 50 miles without problems then things get crazy. Not all issues happen at the same time or all the time. They may last for 5 mins or longer. After sitting the vehicle is usually fine for a few days.

Symptoms:
Check Eng Light
Service ‘Traction Control’ Warning.
Service ‘Stability Control” Warning.
Transmission will not start (from stop) in first gear. Feel like third. Takes forever to get to 20mph.
Transmission will not shift out of first gear from start. Eventually changes gear.

Speedometer rapidly bounces back and forth from zero to current speed while maintaining same speed.
Power door locks unlock and lock repeatedly.
A/C compressor stops blowing cold but fan works.
Main dashboard vents will not blow any air. (Floor and windshield/defrost vents will blow air)

Codes Thrown:
P0700 – TCM Malfunction

U1010 – Lost Communication with TCM

U0073 – Control Module Communication Bus “A” Off

U0100 – Lost Communication with ECM/PCM ‘A’

Not really sure where to start here.
Just start changing modules?

• This topic was modified 11 months, 3 weeks ago by  brian smith.
• This topic was modified 11 months, 3 weeks ago by  brian smith.
• This topic was modified 11 months, 3 weeks ago by  brian smith.

Topic

[EricTheCarGuyKeymaster]

Intermittent electrical problems are hard to pin down. In a situation like yours, I would start by checking the battery. A bad battery can cause all kinds of issues. Once you are sure the battery is good, I’d recommend checking all the body grounds to make sure they are secure and free of corrosion. If the problems still persist after doing that, then I’d start taking a closer look at the modules and wiring involved with the circuits you’re having issues with.

More info on solving problems like this here: http://www.ericthecarguy.com/faq/solving-automotive-electrical-problems

Good hunting and please keep us updated.

[Author]

Replies