Seat Occupant Sensor: Description and Operation

OCCUPANT CLASSIFICATION SENSOR (OCS) SYSTEM

CAUTION: It is necessary to carry out the OCS system reset when a front passenger seat cushion is disassembled, a new trim cover installed or an OCS service kit is installed. A scan tool is used to trigger the active command to carry out the OCS system reset.

NOTE: To identify between a production OCS system and a OCS system service kit, inspect the OCS module electrical connector.

A production OCS system allows the disconnect of the electrical connector from the OCS module.

An OCS system service kit (OCS service kit) has the OCS module electrical connector glued to the module, it cannot and should not be disconnected or altered.

The occupant classification sensor (OCS) system is found only on the front passenger seat. The front passenger seat OCS system is comprised of a silicone gel-filled bladder mounted between the seat cushion foam and pan, a pressure sensor that is mounted to the seat frame and an OCS module which is also mounted to the seat frame. Pressure is applied to the OCS system 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 system pressure sensor, then electronically communicated to the OCS system module. Based on preprogrammed set points the OCS module will inform the restraints control module (RCM), via a high-speed controller area network (HS-CAN), of the necessary information. The RCM uses this information in determining if the passenger air bag module is to be deployed in the event of a deployable collision. The RCM may also use this information to illuminate/not illuminate the passenger air bag deactivation (PAD) indicator.

The OCS module monitors the OCS system for faults and communicates on-demand and continuous diagnostic trouble codes (DTCs) via the data link connector (DLC) with the use of a scan tool.

The OCS system also interprets a variable voltage signal provided by the safety belt tension sensor to identify the presence of a cinched child safety seat in the front outboard passenger seat installed according to manufacturer instructions. The OCS system then communicates with the RCM, automatically deactivating the passenger air bag module. Refer to Safety Belt Tension Sensor. Safety Belt Tension Sensor

The OCS system is also used for operation of the passenger Belt Minder. To deactivate or reactivate the passenger Belt Minder feature, refer to Instrument Panel, Gauges and Warning Indicators or the owner's literature.

The OCS system components (seat cushion foam pad, bladder with pressure sensor, seat wiring harness and electronic control unit) are calibrated to each other and are serviced as an assembly. OCS system components are not to be installed separately. If installing a new OCS system, OCS system component or seat cushion foam pad, a new OCS system service kit (seat cushion foam pad, bladder with pressure sensor, seat wiring harness and electronic control unit) must be installed as an assembly.