Airbags

B0070 — Driver Seatbelt Pretensioner Circuit Fault (SRS)

Severity: medium Safe to drive

What B0070 means

The supplemental restraint system (SRS) module tests its squib circuits and crash sensors every time the ignition is switched on. B0070 is stored when it finds a problem in the driver seatbelt pretensioner control circuit or a related sensor circuit, such as an open, short, high resistance or lost signal. The exact code wording varies by manufacturer, so confirm it in the service information for your vehicle.

Symptoms

  • SRS (airbag) warning light on in the instrument cluster
  • Seatbelt warning indicator may be lit or flashing
  • Engine and transmission behave normally
  • Fault appeared after a minor front impact or interior work

Possible causes

  1. Damaged wiring or corroded connector in the pretensioner circuit (most common)
  2. Loose or poorly seated connector
  3. Faulty driver seatbelt pretensioner
  4. Damaged or faulty front impact sensor or its connector at the radiator support
  5. Poor power or ground supply to the SRS circuit
  6. Faulty SRS control module

How to diagnose

  1. Scan with a tool that supports SRS and record all codes and freeze-frame data if available
  2. Inspect the front of the vehicle for collision damage, especially impact sensors and wiring at the radiator support
  3. Check impact sensor and seat/pillar connectors for corrosion, bent pins and incomplete seating
  4. Check battery voltage and the SRS module ground
  5. Disconnect the battery and wait the time specified by the manufacturer before unplugging any SRS connector
  6. Measure circuit resistance only with the tools and method the manufacturer allows; never probe a pretensioner with an ordinary meter
  7. If wiring is good, test with a known-good sensor or pretensioner
  8. After repair, clear the code and confirm the SRS light goes out and stays off

Common fixes

  • Repair wiring or replace the damaged connector
  • Replace the impact sensor if damaged or after a collision
  • Replace the driver seatbelt pretensioner
  • Replace or repair the SRS control module
  • Clean terminals and restore the ground connection

Questions and answers

Can I drive with B0070 and the SRS light on?

The car will run normally, as the engine and brakes are unaffected. But the pretensioner and airbags may not work in a crash, so have it diagnosed soon.

Can I test the pretensioner circuit with a multimeter?

No, that is dangerous because test current can set off the squib. SRS connectors should be handled with the battery disconnected and per the manufacturer's procedure, or by a professional.

Why did B0070 appear after a minor hit?

The impact may have damaged a front sensor, its connector or the wiring near the radiator. Even without visible damage, a contact can be disturbed, so inspect the harness and sensors.

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.