On my 97 corvette. I bought a used pcm and am not sure how to do all of this. I have efi live. Do I have to just flash in my VIN and do a calibration flash or do I have to do the operating system flash? Also what is this BCM relink that I am told I have to do?

Oh Jr, this is Marc with the trans am that you tuned just if you were wondering. Anyway thanks in advance.

First it depends on if the trannie type in the PCM is the same as your car.
Best is to download that PCM, see what trannie it is and also what the code segments are. Its possible it has new patches in it or maybe really old ones.

Best of course is to do a full flash with all software segments with newest GM code segments whichs assures problems they fixed are in the flash used

If the flash is emailed to me I can tell everything about it.

The PCM was configured for a different vette so its possible when you use it in your car it may need a PCM to BCM relearn, which also resyncs the code for VATs and also may need a crank sensor relearn done to sync the rotation of your sensors code into the PCM being put in

BCM / PCM relearn can be done manually, CKS relearn requires a scanner or Tech-II to send the relearn command.

If the PCM/BCM are not sync'd the car may not even start as BCM as a different key VATs code thus relearn must be done

If CKS is wrong then there will be a ton of misfires, esp at startup/idle.

You could get away with having a different VIN # in the PCM, best case of course is to force flash and change it to match car

Do not believe the BS that no relearn has to be done, best case it do the relearns to assure all modules marry and sync up.

Use search on this forum to fine the PCM/PCM relearn which takes about 33 minutes of key on/off cycles.

CKS must be done after that and is done at idle bouncing off rev limiter while scanner is sending the CKS relearn command

thanks for the reply Jr, The PCM is from a 6 speed car and mine is an automatic. So then it would be best just to do the full operating system flash? I have a buddy that can do the crank relearn for me. Oh, I have an operating system from a 98 vette downloaded on my laptop. I was told it will work just fine. Is this true?

97 and 98 are the same PCM. 1999 began using a different PCM and wiring pinout.

You need to force flash the whole OS segments and calibration.
I would keep the 98 VIN # because if the car ever went to a dealer and a Tech-II is used and if you used the 97 vin then the tech-II or SPS would flash 97 code back into it

For my 99 LS1 I used a 2003 LS6 flash and use a 2003 VIN ID.
This also helps when using a smart OBD scanner like Ease to use the correct PIDs for a 2003 being it goes by what the VIN ID is

If PCM is out of sync with BCM the security light on dash will not flash like it should and could set like a 1636 DTC

Ok so if the PCM ends up being out of sync with the BCM is that when I have to do the BCM relink? I know on my EFI live it has a place to do that but what is happening while doing the relearn or relink?

Not a relink, a relearn so that PCM and BCM learn and exchange VAT codes. If car starts then relearn is not needed, if it needs the relearn follow the GM relearn process.

where can I find the info on how to do the PCM/ BCM relearn?

Do three cycles of key ON for 10 minutes then key OFF for 30 seconds,
repeat this 3 times, thus about 32 minutes so make sure battery is fully charged up before doing this.
Make sure everything else is turned off to limit current draw