B00C4 code meaning
Passenger Seat Occupant Classification Sensor E
What B00C4 means
B00C4 stands for the fifth and last passenger seat classification input; no public carmaker source uses it. Two field cases show what goes wrong besides wiring. Mazda found on 2016–2019 models that a phone, tablet or laptop lying on an empty passenger seat could make the system see a person: the passenger belt warning came on while PASS AIRBAG OFF stayed dark, and the advice was simply to keep devices off the seat. Land Rover quarantined 2025 Range Rover Sport SV cars because the OCS modules had been calibrated with the wrong weight, so the bag might not be switched off for a child seat as FMVSS 208 demands; new modules took 1.1 h. Calibration and plausibility therefore matter as much as the sensor. With B00C4 stored, the airbag lamp is lit and E is not trusted.
B00C4 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 B00C4
- Airbag warning lamp on
- Passenger belt warning or airbag status lamp does not match who or what is on the seat
- Safety note: passenger airbag may stay enabled for a child seat; disconnect only de-energised, calibrate with the maker's procedure after any module change, specialist workshop only
Common causes of B00C4
- PossibleClassification module calibrated wrongly or not at all after replacement
- PossibleOpen or high-resistance contact on the lead to input E
- Less likelyElectronic devices or other objects on the seat confusing the sensing
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Passenger classification sensor eSRS seat wiringOccupant classification module
What each part of B00C4 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). |
| C4 | The exact fault in that area. |
What to do next
- Note B00C4 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 B00C4
What does B00C4 mean?
B00C4 means "Passenger Seat Occupant Classification Sensor E". B00C4 stands for the fifth and last passenger seat classification input; no public carmaker source uses it. It is a generic code, so it means the same on every make.
Is it safe to drive with B00C4?
B00C4 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will B00C4 fail an emissions test?
B00C4 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 B00C4 to fix?
Difficulty: workshop only. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will B00C4 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.