B00B9 code meaning
Driver Seat Occupant Position Sensor C
What B00B9 means
B00B9 is the third occupant position sensor of the driver seat. No carmaker publishes it. A third input could judge posture from the seat back: a patent now held by Joyson places two electric field electrodes under the seat-back cover, one across the upper middle and inboard side and one along the outboard edge, and combines them with seat weight to block the side airbag when a small occupant leans into its path. Honda applied the same idea on the passenger side with OPDS sensors in the seat-back, which must be initialised after the cover or sensor is replaced and can be upset by a damp seat. Whether a driver seat uses the letter C for such an electrode is not documented. A stored B00B9 brings on the airbag lamp.
B00B9 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyWorkshop only
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of B00B9
- Airbag warning lamp on
- Side airbag suppression for leaning occupants unavailable
- Safety note: airbag system with seat side airbag; disconnect seat plugs only de-energised; initialise/calibrate after sensor or cover replacement, specialist workshop only
Common causes of B00B9
- Most likelySeat-back cover or sensor replaced without initialisation
- PossibleDamaged seat-back harness or plug under the seat
- PossibleDamp seat or accessory seat cover disturbing the electric field
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Driver occupant position sensor cSRS seat wiringSRS control module
What each part of B00B9 means
| B | Body system: airbags, seat belts, power seats, lights and climate control. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| B9 | The exact fault in that area. |
What to do next
- Note B00B9 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about B00B9
What does B00B9 mean?
B00B9 means "Driver Seat Occupant Position Sensor C". B00B9 is the third occupant position sensor of the driver seat. It is a generic code, so it means the same on every make.
Is it safe to drive with B00B9?
B00B9 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will B00B9 fail an emissions test?
B00B9 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is B00B9 to fix?
Difficulty: workshop only. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will B00B9 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.