Airbags

B0071 — Seatbelt Pretensioner Deployment Control Circuit Fault

Severity: high Drive with care, to a shop

What B0071 means

The SRS control module detected a fault in the circuit that fires the first-row center seatbelt pretensioner. Normally the module continuously tests this circuit and, in a crash, sends a pulse to the pretensioner to tighten the belt. When a fault is found, the module may disable that function.

Symptoms

  • Airbag/SRS warning light on or flashing
  • Seatbelt or pretensioner warning message
  • Pretensioner may not fire in a crash
  • Light stays on after the engine starts
  • Fault returns after seat or interior work

Possible causes

  1. Damaged wiring or corroded connector under the seat
  2. Failed SRS control module
  3. Faulty or physically damaged pretensioner
  4. Poor power supply or ground to the SRS module
  5. Software corruption or outdated calibration
  6. Mechanical damage from an impact or bodywork
  7. Damaged crash sensor or mounting bracket

How to diagnose

  1. Scan all modules with an SRS-capable tool and save freeze-frame data
  2. Disconnect the battery and wait the time the manufacturer specifies before touching SRS connectors
  3. Inspect the pretensioner harness and connector for corrosion, damage and loose locks
  4. Check whether the harness was disturbed during seat or interior work
  5. Test SRS module power and ground
  6. Check circuit resistance only with the factory method, never probing the pretensioner with a standard meter
  7. Check for module software updates
  8. Clear the code and confirm it does not return

Common fixes

  • Repair wiring and clean or replace connectors
  • Reflash or update the SRS module software
  • Replace the seatbelt pretensioner
  • Replace the SRS control module
  • Replace a damaged crash sensor or its bracket

Questions and answers

What does B0071 mean?

The SRS module found a fault in the control circuit of the first-row center seatbelt pretensioner. The cause can be wiring, the pretensioner itself or the module.

Can I drive with code B0071?

The car will run normally, but crash protection may be incomplete. Have it diagnosed as soon as possible.

Can I test the pretensioner circuit myself?

No. Pretensioners are pyrotechnic and can be fired accidentally. Work must follow the service manual with the battery disconnected, and circuit testing is best left to a professional.

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.