Body, generic

B00A0 Occupant Classification System

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

B00A0 is the catch-all code for occupant classification, the function that judges at the front passenger place whether the passenger airbag may fire and with what force, as FMVSS 208 demands for advanced airbags. Mitsubishi lists it as OCCUPANT SENS UNIT with ten subtypes, among them sensor faults (-02/-09), low supply or unfinished zero-point reset (-22, battery at 9 V or less), lost communication (-83/-86/-87/-88) and a reset error (-93); most are set after 2 s with the ignition on, -88 after 5 s and -87 after 10 s. Mazda traced B00A0:09 on the CX-3 and CX-5 to a sensor too quick to react to low voltage while cranking and replaces the cushion (08-002/23). Nissan reprograms the OCS unit when zero reset fails (NTB19-071D). The airbag lamp lights.

Likely causes

Poor contact or open circuit in the passenger seat harness or plug, often after seat removal
Low battery voltage or voltage dip while cranking (Mitsubishi -22, Mazda B00A0:09)
Zero-point reset not done or not possible after seat work (Nissan reprograms the unit)
Internal fault of the classification sensor or control unit, often replaced with the seat cushion

Symptoms

  • Airbag warning lamp on
  • Passenger airbag status lamp shows the wrong state or the passenger airbag stays switched off
  • Fault may appear only after cold starts with a weak battery
  • Safety note: airbag system; unplug seat and sensor connectors only de-energised; after replacing seat sensors or the unit, the zero-point reset/calibration must be done, specialist workshop only

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€80–1,200
Time0.5–3 h

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

Parts involved

occupant classification moduleoccupant classification sensorsrs seat wiringsrs control module

Related codes

B00A1B00B0B00C0

References: mitsubishitechinfo.com, mitsubishitechinfo.com, mitsubishitechinfo.com, mitsubishitechinfo.com.