interesting....
Here's what the SRT-4 service manual states:
For added system security, each SKIM is programmed with a unique "Secret Key" code. This code is stored in memory and is sent over the PCI bus to the PCM and to each key that is programmed to work with the vehicle.
If a PCM is replaced, the unique Secret Key data must be transferred from the SKIM to the new PCM using the PCM replacement procedure.
I guess its possible that the LX cars might not have this "added security" feature.
So which methodology do the Trucks use?