New PCM? I messed up!

**Workshop** · 03-19-2011

First off,
Thanks Dave for your help thus far and I'm hoping to find a way out of the hole I have dug.

Grand Prix 2001 GT 3800 was experiencing what I thought were transmission issues so I bought a new to me 4T65E transmission from a 2005 Grand Prix. After flushing, filter change, and install I still had the same issues, and then found out that it was just a plugged cat. fml

So now I have a 2001 GT with a 2005 transmission and the PCM is throwing the P1810 error code, because it doesn't like the electrical stuff going on inside the transmission. Dave thinks that as a work around I can use a PCM from a 2003 Grand Prix, but would have to reprogram the final gear ratio to a 3.05.

Here's my questions:
1.) Which PCM 12209624 or 12583827?
2.) Will this actually work? (not that I don't believe Dave, he comes highly recommeneded)
3.) Should I just put the old trans back in since there's nothing wrong with it?

**gtpinsc** · 03-19-2011

dave as in triple edge performance dave?

**Workshop** · 03-19-2011

That is who gave me the idea of the work around. My wife and I are a young couple and tried to swap transmissions by ourselves. 21 hours later, and nothing thrown at each other I might add, we had a semi functioning car.

However, I strongly feel if we have to put the old one back in I'll be sleeping by myself for a while, so the plan is to avoid that if possible.

**gtpinsc** · 03-20-2011

first of all thats awesome that u and ur "wife" did the trans swap... mine would look at me laugh if i asked her to even hand me wrenches under the car.

ok heres my theory and i could be and probably am wrong...cant u just get an 05 n/a pcm and call it a day?

and yes u can have gear ratio's tuned into another pcm.