This would be best answered by some one that has done a number of PCM reflashes.
The PCM is expecting a signal from the cars BCM "body control" for a VATS signal. If you are SURE it is VATS and not PASSKEY there are signal generators you can buy to send the PCM the VATS signal. Other then that, you will need to have the PCM reflashed. Depending on the PCM, many of the 1996 PCMs were not flashing friendly. This was due to the memory that was used in early ODBII PCMs.
Look online for 30/50hz VATS signal generators. I think it was 50 for older VATS and 30hz for later ones. http://www.ebay.com/itm/Vat...91557368578&vxp=mtr.
Something like this.
The generators normally require ground, ignition power and the VATS line to the PCM to be wired up. The resistor bypass only works by fooling the BCM that you have the right key. And that is if you have a BCM.
[This message has been edited by cmechmann (edited 04-12-2015).]