Occupant Classification Module: Installation

A non-calibrated Occupant Classification Module (OCM) is the only component of the Occupant Classification System (OCS) that is available for separate service replacement, as outlined in the procedures that follow. The OCS components of the passenger side front seat cushion including the cushion frame, springs, pad, seat weight bladder and pressure sensor, seat cushion foam and the OCM are a factory-calibrated and assembled unit. Once this unit is connected to a vehicle electrically, the calibration settings are uploaded from the OCM and stored in the memory of the Airbag Control Module (ACM). If only the OCM is subsequently replaced, the new, non-calibrated OCM learns the proper calibration settings from the ACM after it is connected to the vehicle electrically.

If any of the remaining OCS components of the passenger side front seat cushion require replacement, they are serviced only as a factory-calibrated, assembled, and tamper-evident service replacement package. This package includes the assembled frame, springs, pad, seat weight bladder and pressure sensor, foam, wiring and a calibrated OCM. When installing this package, always replace all of the existing components with the new components as a unit. Do not attempt to separate or disconnect any of the new OCS components contained in the service replacement package from each other, and do not attempt to reuse any of the replaced components in this or any other vehicle.

Once any of the original factory-installed components except the OCM have been replaced with the service replacement package components, the OCM can only be serviced by replacing the entire passenger side front seat cushion unit with another complete service replacement package. Any time any one of these components is removed or replaced for any reason, the OCM must be re-calibrated using a diagnostic scan tool, the Occupant Classification Seat Weight special tool, and the Occupant Classification System Verification Test. Refer to the appropriate diagnostic procedures.

WARNING: To avoid personal injury or death, on vehicles equipped with airbags, disable the supplemental restraint system before attempting any steering wheel, steering column, airbag, occupant classification system, seat belt tensioner, impact sensor, or instrument panel component diagnosis or service. Disconnect and isolate the battery negative (ground) cable, then wait two minutes for the system capacitor to discharge before performing further diagnosis or service. This is the only sure way to disable the supplemental restraint system. Failure to take the proper precautions could result in accidental airbag deployment.

WARNING: To avoid personal injury or death on vehicles equipped with the Occupant Classification System (OCS), only the Occupant Classification Module (OCM) and the seat cushion trim may be serviced separately. All other components of the passenger side front seat cushion assembly must be serviced only as a complete factory-calibrated, assembled and tamper-evident service replacement package. This package includes the frame, springs, pad, bladder and pressure sensor, foam, wiring and a calibrated OCM. When installing this package always replace all of the existing components with the new components as a unit. Do not attempt to separate or disconnect any of the new OCS components in the service replacement package from each other, and do not attempt to reuse any of the replaced components in this or any other vehicle. Failure to take the proper precautions could result in failure of the passenger airbag to deploy when required, or in passenger airbag deployment when not required.

CAUTION: On vehicles equipped with the Occupant Classification System (OCS), never replace both the Airbag Control Module (ACM) and the Occupant Classification Module (OCM) at the same time. If both require replacement, replace one. Then perform the supplemental restraint verification test before replacing the other. Both the ACM and the OCM store OCS calibration data, which they transfer to one another when one of them is replaced. If both are replaced at the same time, an irreversible fault will be set in both modules.

Carefully position the Occupant Classification Module (OCM) to the OCM bracket that is welded onto the underside of the passenger side front seat cushion frame. See Figure. When the OCM is correctly positioned, the connector receptacle on the module will be pointed forward in the vehicle.
Install and tighten the two screws that secure the OCM to the OCM bracket that is welded onto the underside of the passenger side front seat cushion frame. Tighten the screws to 2 N.m (20 in. lbs.).
Reconnect the passenger side front seat wire harness connector for the OCM to the OCM connector receptacle located on the forward facing side of the module. Be certain that the latches on the connector are each fully engaged.
Reinstall the lock pin into the connector lock tower on the OCM.
Do not reconnect the battery negative cable at this time. The supplemental restraint system verification test procedure should be performed following service of any supplemental restraint system component. (Refer to ELECTRICAL/RESTRAINTS - STANDARD PROCEDURE - VERIFICATION TEST) .
Following successful completion of the supplemental restraint system verification test procedure, perform the Occupant Classification System Verification Test using a diagnostic scan tool and the Occupant Classification Seat Weight special tool. Refer to OCS VERIFICATION TEST - VER 1 table in BODY DIAGNOSTIC PROCEDURES .