1996 jimmy new PCM tranny won't shift now!

[V7V7V7]

I have a 1996 GMC Jimmy 4x4 that would not start. Had it diagnosed and had to replace PCM. I found a used one out of a 1996 Sonoma and put it in. Truck starts fine and runs good now but tranny will not shift. I know if you buy a new PCM you have to get it programmed by a GM dealership. Is that my problem? I had the same problem when i first bought the Jimmy about 2 years ago and took it to a transmission shop. They changed some $250 part and shifted fine after that.
Any help/feedback would be greatly apreciated.
Thanks

[rlith]

Yes, the ECM must be re programmed with a tech II with you VIN number so that it knows what's in the truck. This includes specifics of the transmission, harness, options, etc...

[DelCoch]

Yep, has to be re-programed. I'm in the same boat and the dealer said 40 bucks to re-program it. However, I got a PCM/VCM from the same model and year as mine, with matching numbers, so we'll see how that goes.

[V7V7V7]

Thanks alot guys..Here they want $120 to reprogram it
Let me know how yours go being the same model and all, curious to know if i should of looked for one too and save $120
Thanks again

[rlith]

Originally Posted by DelCoch

Yep, has to be re-programed. I'm in the same boat and the dealer said 40 bucks to re-program it. However, I got a PCM/VCM from the same model and year as mine, with matching numbers, so we'll see how that goes.

They for the most part all use the same number. What th reprogramming is for is your options (RPO codes) Every harness differes slightly from truck to truck, this can be verified by finding the 4 digit tag near the pcm portion of the harness. So while yours may have had lets say harnes 4826, the ecm you got came from a truck which while having similar options had a harness number of 3128...(for instance, my 95 has about 20 different harness numbers listed). So the ECM's are programmed accordingly. Get the ECM flashed with your vin, that way you ensure that all works properly.

[DelCoch]

Originally Posted by V7V7V7

Thanks alot guys..Here they want $120 to reprogram it
Let me know how yours go being the same model and all, curious to know if i should of looked for one too and save $120
Thanks again

Well, I replaced the VCM with a used one and still the same problem - no spark - no signal from the VCM. I guess the used one could be bad, but I need to do some more trouble shooting.

[rlith]

Originally Posted by DelCoch

Well, I replaced the VCM with a used one and still the same problem - no spark - no signal from the VCM. I guess the used one could be bad, but I need to do some more trouble shooting.

Or you need to have it properly programmed.

[DelCoch]

Even without it being programed I'm thinking it should start, or at least send a signal to the coil. Yes - No??