Airbags

B00A0 — Occupant Classification System Fault

Severity: medium Safe to drive

What B00A0 means

The airbag (SRS) control module relies on the occupant classification system, which uses weight or pressure sensors in the seat and a small control module, to decide whether the front passenger airbag should be on and how strongly it should deploy. B00A0 is set when communication with that module, the sensor signal, or its calibration is outside the expected range.

Symptoms

  • SRS/airbag warning light is on
  • Passenger airbag status indicator is wrong or flashing
  • Passenger airbag may be turned off even with the seat occupied
  • Often no other symptoms; the code is simply stored

Possible causes

  1. Faulty occupant weight sensor or classification module in the seat
  2. Open, shorted, or corroded wiring or connectors under the seat
  3. Lost communication between the OCS module and the SRS control module
  4. Seat or sensor replaced without calibration or initialization
  5. Low battery voltage or unstable power causing a false fault
  6. Rarely, a failed SRS control module

How to diagnose

  1. Scan all modules with a tool that supports SRS and note whether the code is current or stored, plus freeze frame data
  2. Check battery voltage and ground connections; charge or replace the battery if weak
  3. Inspect the seat for objects, an improperly installed child seat, damaged covers, or aftermarket seat heaters or covers
  4. Inspect connectors and harness under the seat for corrosion, bent pins, loose locks, and damage from seat movement
  5. View live OCS data and compare readings with the seat empty and occupied
  6. Test power and communication circuits between the OCS and SRS modules using the factory wiring diagram
  7. Run the manufacturer's calibration or initialization procedure, clear the code, and see if it returns

Common fixes

  • Repair damaged wiring and replace corroded connectors
  • Calibrate or reset the occupant classification system with a professional scan tool
  • Replace the occupant classification sensor or module
  • Replace the SRS control module if confirmed faulty
  • Fix power problems by replacing the battery or cleaning grounds

Questions and answers

What does code B00A0 mean?

It points to a fault in the occupant classification system, part of the SRS. The airbag module cannot reliably tell who is in the front passenger seat because of a communication, sensor, wiring, or calibration problem.

Can I drive with B00A0?

Yes, the engine and brakes are not affected. But the passenger airbag may deploy incorrectly or be disabled, so have it diagnosed soon.

Can I just clear B00A0?

You can clear it, but if the cause is still there the code and SRS light will come back. Find the fault first, and always calibrate the system after replacing the seat or sensor.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.