PCM SWAP question

McGMT

Member
Jun 17, 2012
621
ConeKilrAutoX said:
I have an 04 4.2 envoy and I am swapping in a P12 from an 06 TB.

:undecided: Will the 04 BCM and the 06 PCM be friends? or do I need replace the 04 BCM? :confused:

thanks

I don't think that is do-able between those two years because of some modifications done in 06 and I believe the TCM is not integrated in 04 like it was in 06...

Could be wrong and if I am someone will tell ya in a lil bit haha...
 

ScarabEpic22

Member
Nov 20, 2011
728
This is another area Ive struggled with over the years with this swap, it *should* play nice, but no guarantees. That said, for the I6 the PCM controlled the engine and trans until 08 when GM switched to the E67/T42 combo. V8s only had a PCM for 03-04, starting in 05 they used an ECM/T42 combo.

That said, where did you get your 06 engine harness from? The only ones I can find on eBay are stupid expensive.
 

ConeKilrAutoX

Original poster
Member
Dec 8, 2011
1,179
ScarabEpic22 said:
This is another area Ive struggled with over the years with this swap, it *should* play nice, but no guarantees. That said, for the I6 the PCM controlled the engine and trans until 08 when GM switched to the E67/T42 combo. V8s only had a PCM for 03-04, starting in 05 they used an ECM/T42 combo.

That said, where did you get your 06 engine harness from? The only ones I can find on eBay are stupid expensive.

thats some good news. I got my harness from stricker brothers junk yard in ohio. got them down to 125 shipped because he had to cut the blue pcm connecter (with a foot of wiring) off of another 06 trailblazer harness since the other one was damaged. it IS the whole engine harness, I have been matching things up today just to get a feel for everything. it was from a 06 TB 4.2
 

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