Faulty occupant classification sensor E (internal failure or damage from spills or wear); Damaged or pinched wiring harness under the passenger seat; Loose or corroded electrical connector at the sensor or control module; Failed occupant classification module (OCM) or restraint control module (RCM); Seat cushion damage or foreign object interfering with the sensor bladder or mat; Water intrusion or liquid spill into the seat cushion affecting the sensor

DTC codes / B00xx · Airbags, seats, doors, lights and comfort systems / B00C4

B00C4Passenger Seat Occupant Classification Sensor E

Q: What does code B00C4 mean?

Passenger Seat Occupant Classification Sensor E. B00C4 indicates that the occupant classification sensor (OCS) in the passenger seat, specifically sensor E, has reported a fault or implausible signal to the restraint control module. The computer detects this when the sensor's output falls outside the expected range or the circuit has an open, short, or communication error, which can disable the passenger airbag.

B00C4 indicates that the occupant classification sensor (OCS) in the passenger seat, specifically sensor E, has reported a fault or implausible signal to the restraint control module. The computer detects this when the sensor's output falls outside the expected range or the circuit has an open, short, or communication error, which can disable the passenger airbag.

SystemBody

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaAirbags, seats, doors, lights and comfort systems

Symptoms you may notice

Airbag warning light illuminated on the dashboard
Passenger airbag status indicator may show 'off' even with an adult seated
Passenger airbag may be disabled entirely, increasing injury risk in a crash
Often no symptoms besides the warning light
In some vehicles, a chime or message may appear reminding you to check the airbag system
Intermittent warning light that comes and goes with seat movement or moisture

Common causes, most likely first

Faulty occupant classification sensor E (internal failure or damage from spills or wear)
Damaged or pinched wiring harness under the passenger seat
Loose or corroded electrical connector at the sensor or control module
Failed occupant classification module (OCM) or restraint control module (RCM)
Seat cushion damage or foreign object interfering with the sensor bladder or mat
Water intrusion or liquid spill into the seat cushion affecting the sensor

How to diagnose and fix it

Inspect the passenger seat area for any spilled liquids, debris, or physical damage to the seat cushion and sensor wiring.
Check the under-seat wiring harness and connectors for chafing, pinching, or corrosion; disconnect, clean, and reseat connectors.
Use a scan tool to read live data from the occupant classification system and compare sensor E readings with expected values for an empty and occupied seat.
Perform a zero-point calibration or relearn procedure for the occupant classification system as specified by the manufacturer.
If live data confirms an erratic or out-of-range signal, replace the faulty occupant classification sensor E or the sensor mat assembly.
After repair, clear codes and verify the airbag warning light is off and the passenger airbag status indicator functions correctly with a test weight.

What Most Techs Miss on B00C4

A common oversight is assuming the sensor itself is bad when the real problem is a chafed wire under the seat that only shorts when the seat is moved or loaded.
Liquid spills are a leading cause of occupant classification sensor failures, yet many technicians replace the sensor without addressing the corroded connector or module pins.
The code can be set by a low battery or voltage spike during cranking, so always check battery health and clear the code to see if it returns before condemning parts.
On some vehicles, the occupant classification system requires a calibration after any seat or sensor replacement, and skipping this step will immediately reset the code.
A faulty passenger seat belt buckle switch or seat position sensor can sometimes trigger related codes that mimic an OCS fault, so scan all restraint codes before diagnosing.

Can I keep driving with B00C4?

You can generally drive the vehicle, but the passenger airbag may be disabled, so avoid carrying passengers in the front seat until the fault is repaired. Have the system diagnosed promptly to restore full airbag protection.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.