If the engine control module (ECM), powertrain interface module (PIM) and/or the body control module (BCM) are replaced, the new modules must be security linked to each other. If the procedure is not performed, the engine will not crank or run. If the BCM has been replaced then replace and program all of the key fob transmitters for each of the vehicle's keys. The replacement BCM comes with a new security code replacing the code on the vehicle's security card.

With the Tech 2, perform the following procedure:

1. Replace the key fob transmitter for each of the vehicle's keys.
2. Connect the Tech 2 to the data link connector (DLC) and select: Diagnostic / Pontiac GTO/ Body / Body Control Module / Special Functions / Program Key Fobs, and follow the screen instructions to program the key fob transmitters. Refer to Transmitter Programming for further information.
3. When prompted, enter the security code located on the new BCM and follow the Tech 2 instructions. If a valid code is entered, the new BCM and key fobs will now be linked to each other. The key fobs will be write protected by the BCM and can never be link to another BCM.
4. After successfully programming the new key fobs, backup to Special Functions and select Link BCM to PIM and enter the new security code. This will link the new BCM to the PIM and the security information in the PIM will change. Therefore, the PIM and the ECM will have to be linked. Perform a Vehicle Theft Deterrent relearn through SPS Programming. This will link the PIM to the ECM.
5. If replacing the PIM only, the procedure is the same except the key fobs programming procedure is not needed.
6. If replacing the ECM only, security link the ECM by performing the Vehicle Theft Deterrent relearn through SPS Programming.

Without the Tech 2, perform the following procedure:

1. Replace the key fob transmitter for each of the vehicle's keys.

Program the key fob transmitter. Refer to Transmitter Programming in Keyless Entry.

2. Turn ignition ON with a valid key.
3. Leave the ignition in the ON position for 10 minutes. After 10 minutes the car horn will chirp once.
4. Turn the ignition OFF within 5 minutes after the horn chirp and ON again within 5 seconds. If the timing expires for this step, the sequence will be cancelled.
5. Leave the key in the ON position for 10 minutes. After 10 minutes the car horn will chirp twice.
6. Turn the ignition OFF within 5 minutes after the horn chirps and ON again within 5 seconds.
7. Leave the key in the ON position for 10 minutes, after 10 minutes the car horn will chirp three times. During the three horn chirps the BCM and PIM are being linked.
8. Turn the ignition OFF, and wait 5 seconds.
9. Turn the ignition ON and leave the ignition in the ON position for 10 minutes.
10. Turn the ignition OFF, and wait 5 seconds.
11. Turn the ignition ON and leave the ignition in the ON position for 10 minutes.
12. Turn the ignition OFF, and wait 5 seconds.
13. Turn the ignition ON and leave the ignition in the ON position for 10 minutes.
14. The ECM is now ready to relearn the password from the PIM on the next ignition switch transition from OFF to CRANK.
15. Turn the ignition ON. Linking is now completed.
16. Turn the ignition to crank and run engine at idle speed, to confirm the linking procedure has been successful.