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B0052 — Passenger Seat Belt Sensor

Generic OBD-II · all makesBody

Code B0052 indicates a fault in the passenger seat belt buckle sensor circuit. This means the Supplemental Restraint System (SRS) cannot accurately detect whether the passenger seat belt is fastened or unfastened.

Symptoms

What causes it — most likely first

1. Faulty buckle switch

The internal switch within the seat belt buckle has worn out or failed electrically.

2. Damaged wiring

Wires leading from the buckle to the SRS module are frayed, pinched, or broken, often due to seat movement.

3. Contaminated buckle

Debris, coins, or liquids lodged in the buckle mechanism prevent the sensor from triggering.

4. Loose or corroded connector

The electrical connector under the seat is loose or has developed corrosion, interrupting the signal.

5. SRS control module failure

The airbag control module has an internal fault and is incorrectly reporting a circuit error.

How it's diagnosed

  1. Inspect the passenger seat belt buckle for physical debris or mechanical obstructions.
  2. Verify that all electrical connectors beneath the passenger seat are securely seated.
  3. Perform a visual inspection of the wiring harness for signs of abrasion or breaks.
  4. Use a multimeter to test the continuity and resistance of the buckle switch during fastening and unfastening.
  5. Check for open or short circuits between the buckle sensor and the SRS control module.

Code facts & related codes

SystemBody
StandardizationSAE generic — identical on every make

Frequently asked

Does this code affect airbag deployment?

Yes, in many vehicles, a fault in the seat belt sensor may cause the passenger airbag to be disabled or to deploy with an incorrect force.

Should I replace the SRS control module first?

No. The vast majority of B0052 cases are caused by the buckle switch or wiring; the module is rarely the source of the problem.

Can this be fixed by cleaning the buckle?

If the sensor is not triggering because of a foreign object or sticky residue in the latch, cleaning the buckle may resolve the issue.