GM Service Manual Online
For 1990-2009 cars only

Important: Before the passenger presence system (PPS) can be checked for preloads the front passenger seat must be completely empty of all items. The presence of any items on the front passenger seat will affect the calibration and operation of the PPS. When the preload test is perform, the instrument panel cluster (IPC) and dash lights will begin illuminating at varying intensity. This is normal operation during the preload test procedure and does not indicate additional system faults.

If the PPS is replaced or serviced, perform the preload test procedure for the PPS. Refer to Passenger Presence System Preload Test for the preload test procedure.