Five Hundred AWD V6-3.0L VIN 1 (2005)
Seat Occupant Sensor: Description and Operation
OCCUPANT CLASSIFICATION SENSOR
CAUTION:
-
It is necessary to rezero the OCS system when a front passenger seat cushion is disassembled, a new trim cover installed, or an OCS
service kit is installed. A diagnostic tool is used to trigger the active command to carry out rezeroing of the OCS system.
-
Make sure the seat is completely assembled before rezeroing.
NOTE: To identify between a production OCS system and a service OCS system (OCS service kit), inspect the electronic control unit (ECU) electrical
connector. A production OCS system allows the disconnection of the ECU electrical connector. A service OCS system (OCS service kit) has the ECU
electrical connector glued to the ECU, it cannot and should not be disconnected or altered. An OCS system service kit also has an in-line 10-pin
connector between the OCS ECU and the seat wiring harness.
The seat 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 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 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
electronic control unit (ECU). Based on preprogrammed set points, the OCS system ECU 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.
When an OCS system fault is present, the air bag indicator lamp will illuminate or the air bag warning chime will be activated (if an air bag indicator
fault is present). The SRS then defaults the passenger air bag module to ON (activated) regardless of the size of the occupant in the front outboard
passenger seat.
The OCS system components (seat cushion foam pad, bladder with pressure sensor 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 and electronic control unit) must be installed as an
assembly.
The OCS system also interprets a variable voltage signal provided by the safety belt tension sensor to identify the presence of a properly fastened child
safety seat in the front outboard passenger seat. The OCS system then communicates with the restraints control module (RCM), automatically
deactivating the passenger air bag module. Refer to 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 Seat Belt
Systems or the owner literature.
