VATS Relink

 After installing a new ECM in a stock vehicle, a VATS relink is required before the engine will start. The Passkey III Anti-Theft System uses a transponder inside the head of the ignition key. The exciter inside the ignition lock cylinder energizes this transponder when the ignition switch is on. The transponder transmits a unique signature to the Theft Deterrent Control Module (TDCM). If the key signature transmitted is valid, the TDCM will transmit a “fuel enable” password to the ECM. If the “fuel enable” password is correct, the ECM will start the vehicle. 

To perform a Passkey III system relearn, make sure there is a fully charged battery in the vehicle. The battery will be used for 30 minutes without the alternator for charging. Connect a battery charger to the battery to ensure steady power while programming. When performing this relearn, all previously learned keys will be erased. Additional keys may be relearned immediately after the first key has been learned. 

Relearn procedure: 

1. Insert a master key (black head) into the ignition switch. 

2. Turn key to ON position without starting the engine. Security light should turn on and stay on. 

NOTE: Certain vehicles are equipped with a Driver Information Center (DIC) display. The DIC will display a “Start disabled due to theft” message instead of a security light. 

3. Wait for 10 minutes or until the security light or DIC message turns off. 

4. Turn key to OFF position for 5 seconds. 

5. Turn key to ON without starting the engine. Security light or DIC message should turn on and stay on. 

6. Wait for 10 minutes or until the security light or DIC message turns off. 

7. Turn key to OFF for 5 seconds. 

8. Turn key to ON without starting the engine. Security light or DIC message should turn on and stay on. 

9. Wait for 10 minutes or until the security light or DIC message turns off. 

10. Turn key to OFF. The key transponder information will be learned on the next start cycle. 

11. Start the vehicle. If the vehicle starts and runs, the relearn is complete. 

NOTE: If the theft deterrent relearn procedure does not work, please try the procedure again. 

If additional keys need to be relearned: 

1. Turn the master key to the OFF position and remove key. 

2. Insert the next key to be learned. Turn the key to the ON position within 10 seconds of removing the previously used key. 

3. Wait for security light to turn off, it should happen fairly quickly. You may not notice the lamp, as the transponder value will be learned immediately. Remove key. 

4. Repeat steps 2 and 3 for any additional keys.