Component Tests and General Diagnostics

OCCUPANT CLASSIFICATION SENSOR (OCS) SYSTEM ZERO SEAT WEIGHT TEST

Special Tool(s):

Special Tool(s)

WARNING:
- Make sure the occupant classification sensor (OCS) system is at room temperature, defined as 51 °C to 48 °C (41 °F to 118 °F). If the vehicle has been exposed to temperatures outside this range, expose the vehicle to room temperature for 45 minutes prior to carrying out the Zero Seat Weight Test. The room temperature must remain stable. Failure to follow these instructions may result in the incorrect operation of the OCS system and increase the risk of serious personal injury or death in a collision.
- Make sure the front passenger seat repair is complete, the seat is completely assembled, all components (head restraint, seat side shield, etc.) are correctly installed and the front passenger seat is correctly installed to the vehicle before carrying out the Zero Seat Weight Test. Failure to follow these instructions may result in the incorrect operation of the occupant classification sensor (OCS) system and increase the risk of serious personal injury or death in a collision.

CAUTION: Make sure the occupant classification sensor (OCS) weight sensor bolt protection brackets are correctly installed to the seat track and that it does not contact the cushion side shield, wire harness or any other surrounding parts. Failure to follow this instruction may result in the incorrect operation of the OCS system.

NOTE:
- The supplemental restraint system (SRS) must be fully operational and free of faults before releasing the vehicle to the customer.
- The Zero Seat Weight Test is done with the passenger seat positioned in 2 different positions to make sure that there is nothing to affect the performance and operation of the occupant classification sensor (OCS) system.
- The Zero Seat Weight Test verifies the occupant classification sensor (OCS) system measures zero weight for an empty seat. It is necessary to carry out the OCS module Zero Seat Weight Test any time the front passenger seat is serviced, removed from the vehicle or as directed in the procedures.
- If the occupant classification sensor (OCS) module has any on-demand diagnostic trouble codes (DTCs) except C1941 present, the fault condition(s) must be repaired and the DTC(s) cleared before carrying out the Zero Seat Weight Test on the front passenger seat. Failure to follow this instruction will result in an unsuccessful Zero Seat Weight Test and the incorrect operation of the OCS system.

1. WARNING: The following precautions must be taken before carrying out the Zero Seat Weight Test on the front passenger seat.
- Make sure the vehicle is on level ground.
- Do not expose the front passenger seat to sudden temperature changes.
- Make sure the front passenger seat is empty.
- Make sure the front passenger seat is dry.
- Make sure the front passenger seat head restraint is installed.
- Make sure nothing is placed in the map pockets (if equipped) of the front passenger seat.
- Make sure nothing is underneath the front passenger seat.
- Make sure no non-factory installed items (seat covers, DVD screens, etc.) are on or contacting the front passenger seat. If any non-factory items were installed to the seat, remove the item(s) and communicate to the customer that any alteration/modification to the front passenger seat may affect performance of the OCS system.

Failure to follow these instructions may increase the risk of serious personal injury or death in a collision.

Make sure the front passenger seat is empty and there is nothing underneath the seat. Remove any items from the seat that were not factory installed and make sure that the seat is correctly installed in the vehicle.

2. Position the front passenger seat in the first position.
- Position the seat backrest in the upright position.
- Position the seat in the full forward position of seat track travel.
- Position the seat height to its highest position (power seat only).

3. WARNING: Hysteresis (binding or resistance between components) must be removed from the front passenger seat as directed in the procedure prior to carrying out the Zero Seat Weight Test. Failure to follow these instructions may result in the incorrect operation of the OCS system and increase the risk of serious personal injury or death in a collision.

Remove hysteresis from the front passenger seat by firmly hitting the back of the seat head restraint 3 times.

4. WARNING: Make sure nothing is placed on the front passenger seat during the Zero Seat Weight Test. Do not press, touch or lay anything on the front passenger seat until the Zero Seat Weight Test has been completed. Failure to follow these instructions may result in the incorrect operation of the OCS system and increase the risk of serious personal injury or death in a collision.

NOTE: Make sure a minimum 8-second time period has passed after cycling the ignition switch ON before carrying out the Zero Seat Weight Test active command.

Carry out the Zero Seat Weight Test using the scan tool.
- If the system passed, proceed to Step 5.
- If the system did not pass (DTC C1941 Zero Seat Weight Test Failure reported), proceed to Step 7.

5. Position the front passenger seat to the second position.
- Position the seat in the full rearward position of seat track travel.
- Position the seat height to its lowest position (power seat only).

6. Carry out the Zero Seat Weight Test using the scan tool.
- If the system passed, repair is complete. Proceed to Step 8.
- If the system did not pass (DTC C1941 Zero Seat Weight Test Failure reported), proceed to Step 7.

7. NOTE: Check the repair history of the vehicle for any previous repair that required the removal or service of the passenger seat. The repair history may lead to an area of concern.

Inspect the following for causes of a unsuccessful Zero Seat Weight Test.
- Make sure the front passenger seat is empty and there is nothing underneath the seat. Remove any items from the seat that were not factory installed and make sure that the seat is correctly installed in the vehicle.
- Make sure the seat wiring harnesses are routed and secured correctly and are not twisted, pinched, pulling down or pushing up on any seat component. Refer to Seat Cushion Wire Harness Routing - Front Passenger Cushion in the General Procedures of Seats.
- Make sure the OCS weight sensor bolt protection brackets are correctly installed to the seat track and are not contacting the cushion side shield, wire harness or any other surrounding parts.
- Make sure the seat track and backrest frame are not bent, twisted or damaged.
- Move the seat and backrest to all seating positions. Make sure the seat track does not bind or have any resistance when moved to all seating positions. Make sure that there are no obstructions contacting any seat component when the seat is moved to all seating positions.
- Make sure the seat is assembled correctly and all fasteners are tightened to specifications.
- If a concern was found, repair as necessary, proceed to Step 1.
- If no concern was found, install a new passenger seat track assembly with OCS weight sensor bolts. Refer to Seats.

8. Prove out the supplemental restraint system (SRS) as follows:

Turn the ignition switch from ON to OFF. Wait 10 seconds, then turn the ignition switch back to ON and visually monitor the air bag warning indicator with the air bag modules installed. The air bag warning indicator will light continuously for approximately 6 seconds and then turn off. If an air bag SRS fault is present, the air bag warning indicator will:
- fail to light.
- remain lit continuously.
- flash at a 5 Hz rate (restraints control module [RCM] not configured).

The air bag warning indicator might not light until approximately 30 seconds after the ignition switch has been turned from the OFF to the ON position. This is the time required for the RCM to complete the testing of the SRS. If the air bag warning indicator is inoperative and a SRS fault exists, a chime will sound in a pattern of 5 sets of 5 beeps. If this occurs, the air bag warning indicator and any SRS fault discovered must be diagnosed and repaired. Repair any unresolved DTC(s).

Clear all continuous DTCs from the RCM and OCS modules using a scan tool.