PCM swap help!

[krector88]

I've done a lot of research on this but cannot find a good solid solution. So here's what's going on. I am trying to take the PCM out of my 2002 ZR2, and trying to make it work in my 2002 CC, without having to pay to have it rehashed. My reason for the swap is the PCM out of my ZR2 is the 0411 PCM, and this PCM has been tuned for performance. My CC with 31x10.50's runs nothing like my ZR2 does with 35x12.50's. I've got the entire ZR2 truck so I can rob whatever tells the PCM that it's not in the same truck, or anything else I may need. When I plug the donor PCM in my CC, it obviously won't start. Does the security relearn procedure, by turning the key on until the security light goes out (10 minutes), then turn the key off for 10 seconds and repeating those steps 3 times, really work? Has anyone successfully completed this relearn procedure after swapping PCM's? I also pulled a viper alarm module out of my ZR2, would this module bypass my VATs so I can use this PCM? I also read on gmupfitters how-to splice an on/off switch into the anti theft deterrent. Has anyone successfully completed this mod? I would appreciate reply's only from those who know what they're talking about. No offense, but I'm done with the guessing game on this subject. Any help would be greatly appreciated. Many thanks!

[LoneWolf04]

Is the security light flashing when you're trying to start it? When doing the BCM swap from a blazer with tow haul mode I had to do the key relearn because that's what looks for the key signal. So yes, doing a key relearn does work in that fashion and no scan tool is needed. I would double check the procedure though. I can't remember if the door had to be opened or shut during the procedure.

[krector88]

Right on, thanks for the info. Does the PCM have to be flashed before I can use it in another truck? This is where I get confused and can't seem to find a definite answer. What tells the PCM that it's not the truck it came from? I don't understand why I can't change out whatever it is to trick the PCM into thinking it's still in the original truck. Thus, keeping me from having to pay to have it flashed. Appreciate the info!

[LoneWolf04]

The security code in it is what tells it it's not the original from the truck. That's what the security relearn does. I've got the same year truck as you and the BCM I took out of the blazer was a believe a 2000. No vehicle VIN mismatch because they didn't call for it back then. Wasn't til the later 2000s they started doing VIN locks where all modules needed the same VIN to play nicely with each other.

[krector88]

Well the relearn did the trick! That's a lot for the info! Hope this helps someone else in the future. Here is the procedure I performed. Disconnect battery for 30 minutes, install other PCM then reconnect the battery. Place key in ignition and attempt to start, then the security light should illuminate and stay on for up to 10 minutes, when security light goes out turn key off for 10 seconds, then attempt to start to get the security light to stay illuminated. Repeat these steps for a total of 3 times and truck should relearn the security and start on the 4th attempt.

[HenryJ]

Good to know!

[LoneWolf04]

Glad you got her running!