GM Service Manual Online
For 1990-2009 cars only

Synchronization may be necessary due to the security method used by this system. The transmitter does not send the same signal twice. The RKE module will not execute a signal it has been sent previously. This eliminates the possibility of the signal being recorded and played back.

Important: If the transmitter(s) won't work, perform the "RKE System Check" before synchronizing the transmitter(s).

To synchronize a transmitter with a RKE module, simultaneously press and hold the LOCK and UNLOCK buttons on the transmitter, for approximately five to seven seconds, near your Saturn. The door locks will cycle and the horn will chirp four times to confirm synchronization.

Important: If the transmitter(s) is programmed to more than one Saturn, each Saturn must be within transmitter range during synchronization. Otherwise, the transmitter(s) will not work for the Saturn that is out of range.