Mercedes B005213 – Front Passenger Seat Belt Buckle Fault

System: Safety System / Airbag System Component: Seat Belt Buckle (Front Passenger) Model: Mercedes GLA X156

Typical Symptoms

• Airbag warning light illuminated
• Message relating to restraint system
• Passenger safety system warning
• Fault stored in airbag control unit

Fault Codes

• B005213 – Front passenger seat belt buckle malfunction (open circuit)

Possible Cause

• faulty seat belt buckle sensor
• open circuit in wiring
• connector issue under seat
• wiring damage or poor connection

Component Location

The seat belt buckle is located on the front passenger seat, with wiring typically routed under the seat.

Diagnostic Insight

The seat belt buckle sensor is part of the airbag and restraint system, used to detect whether the seat belt is fastened.

An open circuit fault indicates that the system is not receiving a signal from the buckle sensor.

Technicians usually check:

• wiring and connectors under the seat
• seat belt buckle sensor operation
• continuity of the circuit

In this case, the fault was caused by an open circuit in the passenger seat belt buckle system, and replacement or repair of the component was required.

It is important to confirm the root cause before replacing components.
See Mercedes Fault Diagnosis Guide →

Important Note

Faults in the seat belt buckle system may affect airbag deployment logic and passenger safety systems. These faults should not be ignored. Incorrect repair may affect airbag system operation.

⚠ Professional Diagnostic Recommended

Airbag and restraint system faults require specialist diagnostic equipment. The vehicle should be inspected by a Mercedes-Benz dealer or qualified Mercedes specialist.