Airbags

B0056 — Third Row Left Seat Belt Sensor Fault

Severity: medium Safe to drive

What B0056 means

The airbag (SRS) control module monitors the buckle sensor at the third row left seat to know whether the belt is fastened. This feeds the belt reminder and restraint logic. B0056 is set when the sensor signal or its circuit is out of range, such as an open, a short or no signal.

Symptoms

  • Seat belt or SRS warning light stays on
  • Belt chime keeps sounding for the third row left seat
  • Belt status does not change when buckling or unbuckling
  • Message about a restraint system fault

Possible causes

  1. Failed third row left buckle sensor
  2. Damaged wiring with an open or short, often near the seat or side trim
  3. Poor connection or corrosion at the sensor connector
  4. Spilled liquid or debris in the buckle
  5. Rarely, a fault in the SRS module or lost communication with it

How to diagnose

  1. Scan the SRS module and note all related codes
  2. Inspect the buckle for debris, liquid or damage
  3. Check the sensor connector for corrosion, bent pins and a secure fit
  4. Flex the harness and look for chafing or breaks
  5. Test sensor resistance and circuit continuity per the factory wiring diagram
  6. Watch the sensor state in the scan tool while buckling and unbuckling
  7. Clear the code and see whether it returns

Common fixes

  • Clean or replace the buckle sensor
  • Repair the harness or replace the connector
  • Replace the belt assembly if the sensor is not sold separately
  • Replace or reprogram the SRS module if confirmed faulty

Questions and answers

What does B0056 mean?

The SRS module detected a fault in the third row left seat belt sensor circuit. The cause is usually the sensor, its wiring or its connector.

Is it safe to drive with B0056?

Yes, driving ability is not affected. Restraint protection for that seat may be compromised, so have it checked soon.

Can I just clear the code?

Clearing it only helps briefly. If the fault is still there, the code will return, so inspect the sensor and connector.

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.