Generic fault code

B0052 — Passenger seat belt sensor: malfunction

Q: What usually causes code B0052?

Faulty, aged or drifting sensor. The most likely causes come first. Only a check on the car confirms which one is yours.

Q: What are the symptoms of code B0052?

Airbag warning light on. The airbag or pretensioner involved may not deploy in a crash. Sometimes a seat belt warning. These are the usual symptoms of this kind of fault: not all of them always appear, and sometimes you notice nothing.

The control unit stores code B0052 when it detects this fault: “Passenger seat belt sensor: malfunction”.

Indicative severity: HighRestraint systems (airbags and pretensioners)

Updated on October 13, 2026

Reviewed by Daniel Morales, founder of Reprorace SL, on October 13, 2026

What does code B0052 mean?

Airbags and seat-belt pretensioners. With a fault here they may not deploy in a crash.

System: B · Body
Area: Restraint systems (airbags and pretensioners) · Car system: Airbags and passive safety
Type: Generic (SAE J2012 / ISO 15031-6): the same meaning on every make
Indicative severity: High. Diagnose as soon as possible: it may affect safety or cause damage (engine, catalyst, brakes).

What usually causes code B0052?

Faulty, aged or drifting sensor

The most likely causes come first. Only a check on the car confirms which one is yours.

What are the symptoms of code B0052?

Airbag warning light on
The airbag or pretensioner involved may not deploy in a crash
Sometimes a seat belt warning

These are the usual symptoms of this kind of fault: not all of them always appear, and sometimes you notice nothing.

Can I keep driving with code B0052?

Better not, except when you really have to. This fault may affect safety or damage the engine, the catalytic converter or the brakes. See a workshop as soon as possible; if you must move the car, drive gently and only short distances. If the light flashes, the car loses power, makes unusual noises or the brakes or steering feel different, stop somewhere safe and call for assistance.

This is guidance only: only someone who checks the car can say whether it is safe to drive.

An indicative description of the code's generic meaning. Each manufacturer may give it a different meaning, conditions or tests: always follow its service information and your workshop's advice.

What you can do yourself

For this kind of fault

Do not measure or tamper with airbag circuits, and do not unplug connectors under the seats with the ignition on. Book a workshop as soon as possible.

Read the code and keep the report: with an ECO-LITE in the OBD socket you see it on your phone or computer, with the data captured when the fault happened.
Look for anything obvious: a loose connector, a disconnected hose, a fuel cap not closed properly or a low fluid level. Do not take apart anything you do not know.
Clear the code only after writing it down or after the repair. Clearing turns the light off, but it also deletes the freeze-frame data and the readiness monitors used at the inspection.
Drive normally for a few days and read the codes again. If the code comes back, the fault is still there: book the workshop and bring the report.

Read your car's fault codes on your phone

With an ECO-LITE in the OBD socket you see the codes in your account, with the data captured when the fault happened, and your workshop can check them remotely, always with your permission.

See the ECO-LITE Reserve (presale)

Related codes

B0049Third row right frontal stage 1 deployment control: malfunction
B004AThird row right frontal stage 2 deployment control: malfunction
B004BThird row right frontal stage 3 deployment control: malfunction
B0054Second row center seat belt sensor: malfunction
B0055Second row right seat belt sensor: malfunction
B0058Third row right seat belt sensor: malfunction

B00xx codes: airbags, pretensioners and seat belts

All fault codes