OBD-II trouble code
B0052: Passenger Seatbelt Sensor (Subfault)
The airbag/SRS control module detected a fault in the front passenger seat belt sensor circuit — the sensor that reports whether the passenger is buckled. Airbag and reminder behavior may be affected, so this needs prompt professional attention.
Quick facts
- System
- Body
- Category
- Airbag / SRS Restraints
- Severity
- High severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $100 – $500
- DIY difficulty
- Shop recommended
What does B0052 mean?
B0052 is a body (B) code stored by the airbag/SRS control module — often called the Restraints Control Module (RCM) or SDM (Sensing and Diagnostic Module). Its SAE-generic definition is 'Passenger Seatbelt Sensor,' referring to the switch or sensor that reports whether the front passenger's seat belt is buckled. On the passenger side this signal does more than drive the reminder chime: it works with the occupant-classification/passenger-presence system to help decide how — or whether — the passenger airbag should deploy, so the module monitors the circuit closely.
The module sets B0052 when the passenger seat belt sensor reports invalid data or its circuit falls out of specification — an open or short in the buckle wiring, a corroded or backed-out connector under the passenger seat, a failed buckle switch, or an internal module fault. A symptom byte appended to the code narrows down the exact condition. On some General Motors vehicles this code range is also seen with a 'Deployment Commanded' status that reflects a past crash event rather than a live circuit fault, so read the full code carefully. Because the buckle and harness sit at floor level and flex with seat travel, the usual trouble spots are the connector beneath the passenger seat and the wiring that bends as the seat moves; spilled liquids and aftermarket seat work are frequent contributors.
This is a supplemental restraint fault, not a driveability fault: the car drives normally, but the airbag warning light is on and passenger restraint behavior may not perform as intended. Airbag and pretensioner circuits carry a small risk of unintended deployment when mishandled, so SRS diagnosis and repair should be left to a qualified technician who can safely disable the system.
Common causes
- Corroded, backed-out, or loose connector under the passenger seat
- Damaged buckle wiring where the harness flexes with seat travel
- Failed passenger seat belt buckle switch/sensor
- Moisture intrusion or spilled liquid at the floor/under-seat connector
- Restraint module recording a past deployment rather than a live fault (read the symptom byte)
- Faulty airbag/SRS control module
Symptoms
- Airbag / SRS warning light on
- Passenger seat-belt reminder chime or indicator behaving incorrectly
- Passenger airbag ON/OFF indicator behaving incorrectly on some vehicles
- Stored B0052 fault (often with a symptom byte) in the restraints module
- No effect on engine or driving performance
Diagnostic steps
- 1.Use a scan tool that can access the airbag/SRS module and record B0052 with its full symptom byte and any companion occupant-detection codes.
- 2.Confirm the exact definition for the make and model, and check whether the code is a live circuit fault or a stored 'deployment commanded' status from a past event.
- 3.With the SRS safely disabled per the service procedure, inspect the connector under the passenger seat and the buckle harness for corrosion, moisture, or backed-out terminals.
- 4.Check the wiring that flexes with seat travel for chafing, pinching, or breaks.
- 5.Measure the buckle switch/sensor circuit against specification to separate a wiring fault from a failed buckle.
- 6.If a passenger occupant-classification or tension-sensor code (such as B0061) is also present, treat the passenger seat restraint circuits as a set and look for a shared connector or ground.
- 7.Repair the wiring/connector or replace the buckle switch, then clear codes and confirm the SRS light stays off.
Repair cost
$100 – $500
A connector or wiring repair can be modest, while a replacement passenger seat belt buckle with its integrated sensor commonly runs $150-$400 including diagnosis. SRS diagnostic time typically runs $100-$200. If the code reflects a past deployment rather than a live fault, the module may need service instead. This is airbag/SRS work, so plan for professional diagnosis.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with airbag / srs crash sensor replacement preselected. Adjust labor rate and vehicle category to fit your situation.
DIY vs shop
Leave this one to a qualified shop. It typically involves emissions-critical components, refrigerant handling, or other work that requires manufacturer-grade tooling, training, or certification. DIY attempts often produce a more expensive problem than the original code.