2.7 to 3.5 engine swap
 

I bought a 06 that had a 2.7 in it that was no good and swapped it out to the 3.7. The problem I am having is 1 the check engine light is on 2 traction control light is on and 3 it wont shift out of second gear. When I bought the engine it was a complete take out which included the computer and wiring harness. So I have both ecms. Right now I am using the ecm that originally came in the car, the 2.7 ecm, and am having the problems stated above. I have swapped ecms and when I put the ecm for the 3.5 in it the car will run for a few seconds and then die. So I put the 2.7 ecm back in and it runs good except for the problems stated. I talked to the dealership and he tried telling me that the ecms were not interchangable and that the reason that the car would run for a few seconds and die was because the key and the ecm were conflicting. Anybody else done this engine swap and run into these problems? Any help would be appreciated

The usual reason for an engine dying after a couple of seconds is the anti-theft system. It might work if you can retreive the body control module and SKIM module from the donor vehicle. If not, you're going to need to do some major reprogramming.

Thanks for the reply. I am using the ecm that was in the car originally now and it runs fine, its just when I swap it to the one that came from the donor car that it runs and quits.The 2.7 ecm should run the 3.5, and it does.You think I might need to flash the ecm to get rid of the problems?

Being an 06 the PCM and TCM is in one module so U have a TCM that's for a different car and all that good stuff. Also there is no re flashing that will resolve this it will only update the currant software that's in there no it will not change the software to correctly fit the engine trans combo you have.