B00C9: Passenger Seat Occupant Position Sensor "C" (Subfault)

What it means

The restraint module monitors passenger-seat occupant position sensor C as part of its assessment of the occupant’s position. It sets this code when the sensor’s signal or circuit does not meet the module’s expected criteria.

At a glance

• Usually lights the airbag (SRS) or body-system warning light

How it works

Passenger occupant position sensor C is an input to the restraint control module’s assessment of the passenger’s position. B00C9 means the module has found sensor C’s signal missing or outside its expected criteria, so that position input may not be dependable.

Common causes

Most likely first.

1. Failed occupant position sensor
2. Loose or damaged connector or wiring
3. Open or short in the sensor circuit
4. Fault in the restraint control module

Symptoms

• Warning light or symbol related to the affected system
• Comfort or safety function impaired

How to diagnose it

1. Confirm B00C9 and save restraint-module freeze-frame and related codes with an SRS-capable scan tool.
2. Check the scan tool’s live reading for passenger occupant position sensor C and observe whether it responds as specified to changes in seat or occupant position.
3. Inspect sensor C and its wiring for loose connectors, corrosion, pin damage, or harness wear beneath the passenger seat.
4. After following the manufacturer’s SRS isolation procedure, test sensor C’s supply, ground, signal wire, and continuity for opens or shorts.
5. Compare sensor C’s signal with the manufacturer’s specification to determine whether the sensor or circuit is at fault.
6. If sensor C’s readings and wiring are correct, check restraint-module connectors, power, and ground before considering module failure.

Common fixes

• Secure the sensor C connector or repair visibly damaged wiring.
• Repair a confirmed open or short in the sensor C circuit.
• Replace passenger occupant position sensor C if its tested output is out of specification.
• Repair a verified restraint-module connector, supply, or ground problem.
• Replace or reprogram the restraint control module only if tests establish a module fault.

Can I keep driving?

Driving may be possible, but the passenger restraint system may not correctly use sensor C’s position information. Avoid disturbing the seat or its wiring and arrange prompt SRS diagnosis; do not rely on normal airbag operation until the fault is resolved.