Body, generic

B00C9 Passenger Seat Occupant Position Sensor C

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

B00C9 names position sensor C of the passenger seat, and no carmaker lists it publicly. One concept for a third input watches the gap between torso and seat back: a patent first filed by Automotive Systems Laboratory in 1998, now with Joyson, pairs an electric field sensor in the cushion with a capacitive or radar proximity sensor in the back, aimed at the band about 10 to 18 inches above the cushion. While the torso rests within about 2 inches of the back the bag may fire; if it has been away by more than that for over 50 ms, the bag is disabled. If the back sensor keeps seeing someone the cushion sensor misses, the patent treats that as a fault. FMVSS 208 leaves the choice of such sensors to the maker. B00C9 lights the airbag lamp.

Likely causes

Lead to the seat back sensor broken at the hinge or after trim work
Proximity sensor C faulty or its signal disagrees with the cushion sensor
Thick accessory covers or a wet seat back weakening the field signal

Symptoms

  • Airbag warning lamp on
  • Airbag status lamp may change while the passenger leans forward
  • Safety note: airbag system; seat back and sensor only de-energised (ignition off, battery off, wait time), no third-party seat covers over sensors, specialist workshop only

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€100–900
Time0.5–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

passenger occupant position sensor csrs seat wiringoccupant position module

Related codes

B00C8B00CAB00A1B00B9

References: patents.google.com, law.cornell.edu.