Seat Occupant Sensor: Description and Operation

CAUTION: If replacing only the front passenger seat cushion trim cover, the seat occupant classification sensor must be rezeroed.

The seat occupant classification sensor is found only on the front passenger seat and is not equipped on all vehicles. A white tag having the letters "OCS" (Occupant Classification Sensor) will appear under the front of the passenger seat to identify a seat equipped with a seat occupant sensor. When servicing a passenger seat equipped with a seat occupant classification sensor, the Supplemental Restraint System (SRS) must be deactivated according to Supplemental Restraint System (SRS) Deactivation and Reactivation in the General Procedures portion.

The front passenger seat occupant classification sensor (OCS) is comprised of a silicone gel-filled bladder mounted in the seat cushion, a pressure sensor that is mounted to the seat frame, and an electronic control unit which is also mounted to the seat frame. Pressure is applied to the OCS bladder when weight of any occupant or object in the front passenger seat is present. The pressure is then transferred through a tube, is sensed by the OCS pressure sensor, then electronically communicated to the OCS electronic control unit. Based on programmed limits the OCS electronic control unit will inform the Restraints Control Module (RCM) via a High Speed Controller Area Network (CAN) if the or passenger air bag module is to be deactivated. The RCM uses this information in determining if the passenger air bag module or passenger seat side air bag module is to be deployed in the event of a deployable collision.