[991.1le]

Has anyone run into this issue before? My car is totally bricked at the moment and I’m not sure where to go next aside from just ordering new modules and seeing what happens. This could get… expensive.

Last weekend while unloading my car off the trailer, I had no power steering and a “Service Power Steering” error. I plugged in my GM scan tool, and while using the MDI software to pull the codes, the car started freaking out. Service suspension, rear axle, stabilitrak, fuel level low, etc. Now I’m finding I can’t communicate with most of the modules in the car. HP Tuners VCM scanner and editor can’t see the car at all, and scanning with the GM tool shows no communication with the ECU and about a dozen other modules. I verified 60 ohm across pins 16 and 4 of the OBD2 connector so it seems like the CAN bus is in tact. Any clues? I’m hoping I didn’t somehow fry every single module in the car. I tried 2 different batteries that I verified good and fully charged on a tender, so it doesn’t seem to be that. The car is a 2018 SS 1LE.

[Vtor_ZL1]

Sure it's not just dead or near dead battery ?

[ctrlz]

A couple of links which may help. There is a note about one of the sensors shorting to ground and causing all the other modules which rely on a 5V reference to go "off-line."
https://www.underhoodservice.com/ecm...cation-issues/
https://rustyautos.com/obd-wont-connect-to-ecu/

[991.1le]

Originally Posted by Vtor_ZL1

Sure it's not just dead or near dead battery ?

Yeah tried a couple different know good batteries with the same result.

Originally Posted by ctrlz

A couple of links which may help. There is a note about one of the sensors shorting to ground and causing all the other modules which rely on a 5V reference to go "off-line."
https://www.underhoodservice.com/ecm...cation-issues/
https://rustyautos.com/obd-wont-connect-to-ecu/

Thanks for the links! I’m thinking it’s gotta be something along those lines. Right now I have it narrowed down to all devices on the high speed GMLAN. All of the modules that communicate on the low speed network are talking just fine.