You can relearn the new key/barrell. No need to start splicing anything. Now since I remember seeing Passkey on my old 92 , I don't thinkt he VATS term applies in later years. So try this out. (Passkey)
More info , read here
http://www.bsecorp.com/files/techtips/ST9303l.pdf
Page 8 reveals PasskeyI/Passkey2 as the same key found in thirdgens , so Vats must be a carryover term from GM in 86'.
THEFT DETERRENT PASSWORD RELEARN
General Motors uses three different types of vehicle theft deterrent systems in their cars and trucks manufactured from 1986.
They are:
1. Pass-key or Passkey 2 (PK2)
2. Passlock
3. Passkey 3 (PK3) or Passkey 3+
Instead of listing all of the vehicles and the systems that they use, we will simplify the identification process by taking a look at the vehicle ignition key (Refer to page 8 for key identification). There is one other system, referred to as VATS (Vehicle Anti-theft System) that is used by GM. This system is similar to Passkey, but since a relearn is not necessary, we will not elaborate on this system in this article. By referring to the chart and matching the correct key, you can safely identify the system that the vehicle uses, and, in turn, determine the correct relearn procedure. Just remember, that this article pertains only to those vehicles with a re-programmable or “re-flashable” PCM.
PASSKEY & PASSKEY 2
This system consists of: the Powertrain Control Module (ECM or PCM), Body Control Module (BCM) or Passkey theft deterrent module, and the ignition lock and key. In most cases, the theft deterrent duties are handled by a Passkey module. In those vehicles, if you are replacing a key, all you must do is match the resistance of the existing key that is in use. If you replace the theft deterrent module, then the module will learn the existing key resistance with the first start up sequence. At that point, the resistance is permanently memorized by the module, and can no longer be changed. No relearn is necessary. In this situation, the vehicle will start and run with no problem. If the vehicle won’t start, check your scan tool for a VTD (Vehicle Theft Deterrent) Fail-Enable Mode trouble code, or if the security light on the dash is illuminated. If you have this code, then the vehicle probably is equipped with a BCM, and you must perform a relearn.
(may not apply)
The next section applies only to those vehicles that use a BCM.
For those vehicles that use a BCM, the BCM can learn the resistance value of the existing key by using the relearn process. In order for the vehicle to start, the BCM (as well as the Passkey module in other vehicles) must identify the resistor pellet in the key, then the BCM sends a password to the PCM. If this password matches the password stored in the PCM, the system enables fuel delivery. So you can see that if either the BCM or PCM are replaced, a relearn procedure is necessary. This same relearn procedure can be used if an ignition key with a different resistance value is used to replace the existing key. Before beginning the relearn, make sure there is a fully charged battery in the vehicle, and both the BCM and PCM are properly powered up and in communication with each other. Now you’re ready to initiate the relearn procedure.
1. First, insert the ignition key and turn the ignition switch to the “On” position (Do not start the engine). Leave the switch on for 11 minutes. The security light may flash or be on steady during this 11 minute period. Make sure the light is no longer on or flashing before proceeding to #2 .
2. Turn the ignition switch off for 30 seconds.
3. Turn the ignition switch to the “On” position (as in step #1) for 11 minutes again.
4. Turn the ignition switch off for another 30 seconds.
5. Turn the ignition switch to the “On” position for 11 minutes a third time.
6. Turn the ignition switch off for 30 seconds one final time.
7. Turn the ignition switch to the “On” position one final time and wait 30 seconds.
8. Attempt to start the engine. If the engine starts and runs normally, the relearn is complete. If the engine does not start, check for trouble codes and address them before attempting the relearn procedure again.
