I have a 2005 LSJ. And i might swap it with a Low mileage 2006 LSJ motor. Will a 2005 GM stage 3 PCM work in that motor. Or does that PCM have nothing to do with the Current harness built into my car. Cause it's known that 2006/07 model PCMs don't work with 2005 cobalts. Didn't think anyone covered this

 

05 06 same 07 different

 

Supposedly that pcm reads gas tanl backwards for some reason if the pcm is wrong but how does the car know what pcm its running from what year

 

im pretty sure the pcm is tied in with the bcm and the other computers in the cann system in the car the software is different in 07

 

If youre putting the 06 motor in your car, then you dont have to worry about the gas gauge. You can use your 05 PCM without issue.

As far as compatibility is concerned, 05 and 06 are more alike than 06 and 07 are. The only reason I can imagine GM separted the GMS3 PCM's into 05 and 06/07 is due to the gas gauge thing. Otherwise there would have been a single GMS3 OS. 07 is indeed different, but you can successfully run an 06 tune on an 07 without issue. I'm doing it right now and there are no ill effects. FYI.. little secret... GMS3 for 06/07 is simply an 06 tune, and there is no such thing as a 32-bit 07 OS or PCM.

 

just wondering. Might have Trifecta or Hptuner guy Tweek my GMS3 tune when my car is Finished, Just wondering so i can sell it now. otherwise ill use it