swapping pcms now wont start

[Trevor]

Do i need to do a crank relearn? I suspected my stock pcm of needing a reflash so i got another stock pcm with same service number and same motor for free. trying to swap them now truck tries to crank but wont run.

[Melissa@NelsonPerformance]

try a Security relearn
Nelson Performance - Security Relearn for no start

[Trevor]

ill have to try that later gotta go to work so had to throw the old pcm back in.

[Trevor]

Should it work after doing this? Or is it not possible to use a diff pcm?

[dallas]

You can use another PCM.. Make sure though it is from a Tahoe, Suburban, not a van.. I can tell you from experience... I think the VATs??? need to be unlocked, but others will know that.. I have another PCM I bought from an Avalanche. It works fine. I do get a Battery light that flashes in the message center but there is nothing wrong. It all has to do with the options that an avalanche has, I guess..

[Trevor]

Did it crank right up with the new pcm? this one tries to fire but wont stay running and flashes the battery light and security light.

Re install the stock pcm and it will fire right up.

the pcm im trying to use is from a 2000 4.3 sierra

[GasGuzzler]

These don't have VATS. VATS is the old school system that uses the square head key with a pellet.

Anyway...you can swap but at minimum you need to do a theft learn as already stated in the topic by Melly. Even then option content and therefore the stock tune can vary greatly.

Why are we swapping PCM's again?

[Trevor]

to see if it will make my gauges work again. since ive tried almost all the stuff im capable of.

[GasGuzzler]

PCM is not the answer if all the gauges are homoed out.

[Trevor]

Its just the gas gauge temp gauge and the cruise doesnt light on cluster when cruise is turned on. No its not the cluster,wiring,or sending unit or a fuse. All that has been replaced/checked.