Operation CHARM: Car repair manuals for everyone.
Home >> Mercury Truck >> 2009 >> Mountaineer AWD V8-4.6L >> Repair and Diagnosis >> Restraints and Safety Systems >> Air Bag Systems >> Testing and Inspection >> Component Tests and General Diagnostics

Component Tests and General Diagnostics




Occupant Classification Sensor (OCS) System Zero Seat Weight Test






Zero Seat Weight Test

WARNING: Make sure nothing is placed on the front passenger seat during the following procedure. Do not press, touch or lay anything on the front passenger seat until the following procedure has been completed. Failure to follow these instructions may result in incorrect operation of the occupant classification sensor (OCS) system and increase the risk of serious personal injury or death in a crash.

NOTE: The Supplemental Restraint System (SRS) must be fully operational and free of faults before releasing the vehicle to the customer.

1. WARNING: The following precautions must be taken before carrying out the following procedure on the front passenger seat:
- Park the vehicle on level ground.
- Make sure the occupant classification sensor (OCS) system is stabilized at a temperature in the range of 5°C to 48°C (41°F to 118°F) and is not exposed to temperatures outside that range.
- Make sure the front passenger seat is empty and dry.
- Make sure the front passenger seat repair is complete and all attached components (head restraint, seat side shield) are correctly installed.
- Make sure the front passenger seat occupant classification sensor (OCS) rail shields are correctly 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 the under-seat body wiring harness and seat wiring harness are not twisted or pinched between the electrical bracket and the No. 2 crossmember, or are not twisted or pinched between the electrical bracket and the floor.
- Make sure no non-factory installed items (seat covers, DVD screens) 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. Refer to the Owner's Literature.
- Make sure the seat is correctly installed in the vehicle.

Failure to follow these instructions may result in incorrect operation of the OCS system and increases the risk of serious personal injury or death in a crash.

Make sure the front passenger seat is empty, 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.
- Position the seat in the middle of seat track travel.

- Position the seat backrest in the most forward position.

- Position the seat height to its lowest position (power seat only).

3. WARNING: Remove binding or resistance between all components of the front passenger seat as directed in the following procedure. Failure to follow this instruction may result in incorrect operation of the occupant classification sensor (OCS) system and increases the risk of serious personal injury or death in a crash.

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

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

NOTE: If the scan tool responds with system passed, do not carry out the System Reset active command.

Cycle the ignition ON, wait 8 seconds and carry out the Zero Seat Weight Test using the scan tool.

- If the system passed, the repair is complete. GO to Step 7.

- If the system did not pass (DTC C1941 Zero Seat Weight Test Failure reported), repeat Steps 1 through 4. If the system did not pass the second Zero Seat Weight Test, proceed to the next step.

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

Cycle the ignition OFF then ON, wait 8 seconds and carry out the System Reset active command using the scan tool.

6. Cycle the ignition switch OFF then ON, wait 8 seconds and carry out the Zero Seat Weight Test using the scan tool.
- If the system passed, the repair is complete. Proceed to Step 7.

- If the system did not pass (DTC C1941 Zero Seat Weight Test Failure reported), install 2 new OCS rails and carry out the System Reset procedure. For additional information, refer to Occupant Classification Sensor Service and Repair and Occupant Classification Sensor (OCS) System Reset Programming and Relearning.

7. Prove out the 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 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.

Clear all continuous DTCs from the RCM and Occupant Classification System Module (OCSM).

pro multis · About Operation CHARM