2002 Sierra

1. Close all doors
2. Insert key into ignition
3. Hold down the power UNLOCK button on the driver's door panel, continue to hold down until instructed to release in step 9.
4. Perform steps 5 through 8 in a fairly rapid succession.
5. Turn the ignition to the ON position (as far as you can go without starting the engine.)
6. Turn the ignition to the OFF position.
7. Turn the ignition to the ON position (as far as you can go without starting the engine.)
8. Turn the ignition to the OFF position.
9. Release the power UNLOCK button on the door panel. The vehicle should respond by door locks locking and unlocking automatically. (If locks do not cycle after you let go, not before you let go of the unlock button, then the vehicle has not entered programming mode and you must start procedure over. Remove key from ignition, open drivers door and return to step 1 ). If the locks do cycle automatically then proceed to step 10.
10. Hold down the LOCK and UNLOCK buttons on the remote until the doors lock and unlock. This may take up to 30 seconds.
11. Repeat step 10 NOW for each additional remote. (Including any existing remotes).
12. Turn the ignition to the ON position to exit the programming mode.
13. Test remote(s).