I had a crank but no start condition on my 2003 supercrew 5.4L a few months ago. Had it towed to the Ford dealer. They diagnosed it as a bad PCM. I sourced a replacement (programmed to my VIN) PCM from Flagship One. The dealer installed the PCM and performed the PATS programming with my keys and the instrument cluster. I believe my truck is a PATS type C.

I have obtained a second PCM programmed to my VIN to carry in my truck as a spare. My question is can I remove the installed working PCM, replace it with the spare PCM, then use FORscan on my laptop to perform the parameter reset to marry the keys, cluster and PCM and have the original PCM still work without having to perform the marry process again? This would make a failure on the road a relative easy repair with the spare PCM If the configuration file/table that captures the cluster, PCM and keys data resides only in the PCM I should be able to just swap the PCM and go since it would have all the correct data. If the file resides in the cluster or the cluster and PCM I would have to repeat the marrying process again. Any thoughts?

I have been hesitant to try this swap for fear of breaking something.
Thanks,
aircooled

 

You'd likely be better off just sending your spare PCM out and having PATS deleted. Takes all of the guesswork out of it.