Service Number on PCM's

[gmforlife]

I know this is probably a stupid question, I have a guy's pcm i am working on some things, i have a pcm guy that matched the service numbers. My buddy's truck is a 2001 GMC Sierra 4.8, the pcm my guy sent me is the same service number but it's a 2002 silverado 4.8. Why can't i change the vin to the 2001? It says different OS number, but it should be the same if it's the same service number right?

[EC_Tune]

Same Service number, Same PCM. Good to go...

[Bill@HPTuners]

http://www.hptuners.com/help/vcm_edi...change_vin.htm

this explains the vin change feature.

[12secSS]

Do a write entire of the file you need. Simply changing the VIN from a 2002 to a 2001 is not allowed, since the OS doesn't match.

[gmforlife]

Same Service number, Same PCM. Good to go...

Yah that's what i figured. It's not that critical to change the vin on it. So it won't be a problem to tune the 2002 pcm and put it in the 2001 truck?

[gmforlife]

Also, i wouldn't have to disable vats for this situation would i?

[EC_Tune]

Yes you will need to change the VIN on it if you want VAT's to work.

[gmforlife]

Yes you will need to change the VIN on it if you want VAT's to work.

But if the vin doesn't match the truck, will it start? So in other words if i don't have the correct year pcm then it won't work?

[gmforlife]

Is there any way to tell on the pcm what year it is. Cause i got the correct service number, but wrong year, so how can you tell?

[EC_Tune]

If you have a read of the tune out of the other PCM you can do a write entire and you're good to go on the 02 PCM. IF the service # is the same you can swap files.

But like stated above, you can't just alter the VIN *unless* the OS associated with it is the same. And GM is really good about changing the OS's from year to year. The calibration engineers have to generate *Evidence of Attendance*... LOL

J/K Greg...

Calibrating at the OEM level is some super difficult stuff. Imagine being handed a piece of hardware and then being told it has to run the vehicle in 4 months...

[gmforlife]

If you have a read of the tune out of the other PCM you can do a write entire and you're good to go on the 02 PCM. IF the service # is the same you can swap files.

But like stated above, you can't just alter the VIN *unless* the OS associated with it is the same. And GM is really good about changing the OS's from year to year. The calibration engineers have to generate *Evidence of Attendance*... LOL

J/K Greg...

Calibrating at the OEM level is some super difficult stuff. Imagine being handed a piece of hardware and then being told it has to run the vehicle in 4 months...

Thanks for the advice, you always help me out man.