B00A0 code meaning
Occupant Classification System
What B00A0 means
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.
B00A0 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 B00A0
- 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
Common causes of B00A0
- Most likelyPoor contact or open circuit in the passenger seat harness or plug, often after seat removal
- PossibleLow battery voltage or voltage dip while cranking (Mitsubishi -22, Mazda B00A0:09)
- PossibleZero-point reset not done or not possible after seat work (Nissan reprograms the unit)
- PossibleInternal fault of the classification sensor or control unit, often replaced with the seat cushion
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Occupant classification moduleOccupant classification sensorSRS seat wiringSRS control module
What each part of B00A0 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). |
| A0 | The exact fault in that area. |
What to do next
- Note B00A0 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 B00A0
What does B00A0 mean?
B00A0 means "Occupant Classification System". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with B00A0?
B00A0 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will B00A0 fail an emissions test?
B00A0 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 B00A0 to fix?
Difficulty: workshop only. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will B00A0 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.