What it means
The restraint control module monitors driver seat occupant position sensor C as part of the occupant position system. It sets this code when it detects a fault in that sensor or its circuit; the title does not specify the failure mode.
At a glance
- Usually lights the airbag (SRS) or body-system warning light
How it works
Driver seat occupant position sensor C is one of the inputs the restraint control module uses to determine the driver's position relative to the airbag. B00B9 is set when the module detects a fault associated with sensor C or its circuit; it does not name a specific failure mode.
Common causes
Most likely first.
- Faulty driver seat occupant position sensor C
- Damaged wiring or connector at the sensor
- Obstruction or damage affecting sensor readings
- 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
- Scan the restraint module and review freeze-frame and live data for sensor C, confirming whether B00B9 is active and whether the sensor value is missing or implausible.
- Look for objects, seat-cover alterations, or visible damage in the driver seat area that could affect sensor C.
- Inspect sensor C's accessible harness and connector for pulled wires, chafing, corrosion, or a loose fit, observing airbag-system precautions.
- Move the driver seat normally while monitoring sensor C data, if the manufacturer's procedure permits, and check whether the reading changes consistently or drops out.
- Test sensor C and its circuit to the manufacturer's specification; investigate the restraint control module only if the sensor and wiring pass.
Common fixes
- Remove anything obstructing driver seat sensor C.
- Repair damaged wiring or a loose or corroded connector at sensor C.
- Replace sensor C if testing confirms it is faulty.
- Repair or replace the restraint control module if sensor C and its circuit meet specification.
Can I keep driving?
Arrange prompt diagnosis because a restraint warning can indicate that the system has lost a driver-position input and may not operate as intended in a crash. Avoid working on seat wiring unless you know the required restraint-system precautions.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.