P2156 code = bad ecm

Aaron Muggelberg · February 18, 2020

I have a 2014 Silverado with the 5.3. Heading up north this week it started flashing check engine light and traction control light, and I could feel a slight miss. Pulled into dealer and had code p2156 (fuel injector group d supply voltage low). Code was not active at dealer. They cleared the code and suggested I keep driving to see if it comes in again. 30 miles later same thing. Lights kept flashing on dash until I pulled over and turned truck off. I wiggled all the wires and started the truck. Engine light was solid. No traction control light. Started driving and could go 10 min before it would act up again and start flashing and have a slight miss. Stop turn truck off and all good for another 10 min. Finished my 100 mile trip upnorth like that. Left 2 days later to drive 300 miles home. Check engine light still on, but no problems. After 50 mile I got gas and light was completely off when I left the gas station. Drove all the way home like nothing ever happened. Took it to dealer today and they said the engine ecm is bad and possibly the brake ecm. ????? Told me cylinder 4 kept loosing ground in the ecm. $680 to fix. Do I just bring it home clean the connections and hope for the best or bite the bullet and replace. Truck is running great now. Could it just be a bad connection at the ecm.

Aaron Muggelberg · February 18, 2020

I was also told my 5 year 100,000 mile warranty expired 2 days ago but it didn't matter because the ecm is only covered in the bumper to bumper 3 year 36,000 mile warranty the truck only has 54,000 miles on it.

tbarn · February 18, 2020

Powertrain Control Module is 8/80 coverage.

Aaron Muggelberg · February 19, 2020

Was able to dig into the paper work when I picked the truck up last night. They checked and cleared all codes but were not able to clear code c0242. The flow chart says clean connections, attempt to clear code. If code does not clear replace k20 engine control module. If code still does not clear replace k17 electronic brake control module. Going to clean all connections this weekend and see if that works first.

TJay74 · February 19, 2020

As said the ECM falls under the Federal emissions warranty coverage of 8yr/80k, not the 3yr/36k like the dealer stated. With that even if it was the ECM and the brake module you cant replace them yourself, the new unit has to be flashed with the OS and firmware and then VIN tied to the vehicle.

Aaron Muggelberg · February 21, 2020

Thanks for clarifying the 8/80 from the previous post. I looked it up and called gm warranty department direct and got the answer I was looking for. They said dealer should have noticed that it was covered not quoted me over $600. Probably were double dipping. Charge customer and collect on warranty claim. Thanks guy for all the help and info.

Aaron Muggelberg · February 28, 2020

PROBLEM NOT FIXED YET. After the dealer accepted that it was a covered under the federal emissions warranty I took the truck in to have the ecm replaced. Got the truck back and headed up north with a trailer full of snowmobiles. 3.5hrs in the check engine light was flashing again with the same problem. I took it to the dealer the day I got home and they said that cyl. 4 injector must be bad and shorting out giving the code. After expressing my pissed of feeling for it not being fixed the first time it was in they knocked the repair down from $800 to $198 after talking to GM about it. They replaced the injector and i picked the truck up. Drove it for 30 or 40 miles and guess what. Check engine light is back on. . Heading back there in the morning again.