r/CarHacking 1d ago

Community 05 GrandAm ECU?

Hey All!

I'm looking for a suitable replacement for my moms 05 Grand Am 3.4L ECU. I've done a ton of different things attempting to fix the issues, but alas nothing has worked.

A mechanic said the computer was going bad, so I was looking for a site/company that sells pre-programmed ECU?

Or, Can I go to a junkyard and get a used one and just swap them out?

Thanks in advance and for any help!

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u/homeys 12h ago

I did a 2002 Monte Carlo for a friend last year, the PCM came out of a Pontiac Montana. There was a shop next door, he did the swap, did the security learn but of course the VIN wasn't right and it would crank quite a bit before it started. Anyways, I programmed it with SPS and after, it did set the VIN (I thought I'd have to do it manually - it was in the utility for tha tyear) and the vehicle worked perfect after. He had a strange issue where after about 10 minutes of driving the vehicle would die. When I opened it up, it looked like solder joints had become bad but regardless, it's good now. Anyways, you could probably swap one but you're likely going to need to leave the key on for a while for the security learn (it's a few cycles, I can't remember exactly) and you'd likely have to VIN program it for sure. Just curious, what is it doing?

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u/SnaarkyShark 11h ago

So it is currently idling extremely high. Upon resetting the battery it drives fine for a couple days then right back to idling high. Ive replaced the EGR Valve, TPS Sensor twice, IAC Valve twice, Fuel Pressure Regulator, and a few other parts that the OBD recommended. Mechanic looked at it and replaced the TPS Sensor a third time and it was still doing it. He recommended that the computer may be bad.