Join Date: Nov 2009
--cypher-- is offline
Re: Can I replace my PCM with a Junkyard PCM
Sorry I'm a little late on this topic, but a few weeks back I had a PCM go bad. I fried it when I tested the fuel pump by jumping the relay--only I got the pins backwards and jumped the PCM instead of the pump. As ridiculous as it sounds, I'm smarter than that. Usually.
Anyway, the truck ('98 Jimmy) would still start and run but only after the oil pressure switch closed. And the transmission shifted wicked-hard; it barked tires between gears. And the Check Engine light kept coming on with an EGR code. I burnt a lot of the PCM, needless to say.
So I went to the junkyard and bought a used PCM (same numbers) out of a Blazer and put it in mine, hoping to drive off with it. No chance. The engine would start but then shut right off. It wouldn't run for more than two seconds.
I took it all to the dealer and paid $84, and haven't had a problem for 2,000 miles now. Shifts fine, fuel pump primes, engine light is off, it's all good.
The short answer in my experience is: no, you can not plug a junkyard PCM in without flashing it to your VIN. Don't sue me, it just my opinion.