Airbags

B00B4 — Driver Seat Occupant Classification Sensor E Fault

Severity: medium Safe to drive

What B00B4 means

The airbag (SRS) control module uses occupant classification sensors in the seat to decide how the airbags should deploy. B00B4 means the signal from sensor "E" in the driver seat is missing, implausible or out of range. It is a subfault code, so the exact cause should be narrowed down with scan tool data and the vehicle's wiring diagram.

Symptoms

  • Airbag (SRS) warning light on in the instrument cluster
  • Occupant classification system error
  • System can't properly determine driver occupant status
  • Code returns after being cleared

Possible causes

  1. Failed driver seat occupant classification sensor E
  2. Loose, corroded or broken connector at the sensor
  3. Damaged wiring harness under the seat (chafed or pinched by seat movement)
  4. Moisture or spilled liquid affecting the contacts
  5. Faulty SRS control module (uncommon)
  6. Missing calibration after seat service or replacement

How to diagnose

  1. Scan all modules with an SRS-capable tool and note any related subfaults
  2. View live seat sensor data and see whether the signal responds
  3. Inspect the harness and connectors under the driver seat for damage, moisture and corrosion
  4. Check for seat covers, heaters or objects under the seat that could interfere with the sensor
  5. Disconnect the battery and wait the manufacturer's specified time before touching SRS connectors
  6. Test circuit continuity and resistance per the vehicle's wiring diagram
  7. Clear the code and confirm it does not return

Common fixes

  • Repair the wiring or replace a damaged connector
  • Replace occupant classification sensor E (or the seat sensor assembly)
  • Perform the occupant classification calibration or zero-point reset with a scan tool
  • Replace the SRS module if the fault is confirmed there

Questions and answers

What does code B00B4 mean?

The airbag control module detected a fault in the circuit of driver seat occupant classification sensor E. This can cause the system to misjudge how the airbag should deploy.

Is it safe to drive with B00B4?

You can drive, since the engine isn't affected. But driver protection in a crash may be reduced, so have it diagnosed soon.

Can I just clear B00B4?

Clearing it may turn off the light briefly, but it will come back if the cause remains. Check the connectors, wiring and the sensor first.

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.