Andy2016

CanHI 2.8 CanLo 2.2, nothing to Chassis ground from Pin 6 or Pin 14, 60 ohm on Pin 6 and 14, checked every connection, cut and removed tape from the middle of the truck to the rear, opened up dash also. Im leaning towards a bad FPCM again. Couldn't be bad straight from GM could it, hopefully warranty is still good, got the new one back in June of 25 and the light and code never went away after clearing codes. I furgured the new FPCM could not be bad and some have said a wiring issue, thats why Im at this point.

Ive been chasing this coms fault for awhile, it's ecm is not communicating with the FPCM, at first I read 120 ohm on 6 and 14, I replaced the FPCM, it was programmed already from GM, replaced end of 2025. Over the past week Ive had time to start by cleaning grounds, removed the wire loom at the rear of the truck to expose all of the wires to the 4 modules above the spare tire, Ive removed all connecters and inspected, after I checked ohms from the resistors through every module with connecters back in. Its weird, must of had a pin that had pushed up, now Im getting 60 ohms, voltage is good also, still not communicating. I have 2 more ground that are on top of the dash to do and see if that fixes it. Ive checked the BCM, FPCM, TRCM, SPCM, ECM, main fuse box connecter, both side dash fuse boxes etc. Any other ideas would be great. Truck is well taking.

Since Condenser replacement Ive had no issue with that, now its the transmission, strut and shock issues and electrical issues. I only have 80K on it and barely drive it.

Add me, 2016 Serria Denali 60k no ac, but I moved from Maryland to South Carolina and didnt have the time to get it fixed and we made a few trips now have 67k. I bought used at 53k, had the trans flushed and updated at 54k. I'm thinking the dealer patched the Ac to get by. I've been adding refrigerant to get by. Like everyone says, Gm should be 100% responsible, I'm a Hvac tech and refrigerant leaks are a no no period, that's from the EPA. I guess that GM in Government Motors of China now that a known leak is ok and requires no attention, that's BS, because if I have a known leak on a system and I'm caught I'm fined. Well any way, this is crazy.