Airbags

B0079 — Driver Seatbelt Pretensioner "B" Deployment Control Circuit Fault

Severity: high Drive with care, to a shop

What B0079 means

The SRS control module tests the driver seatbelt pretensioner's squib circuit every time the ignition is switched on. B0079 is stored when resistance or voltage in circuit "B" is out of range, due to an open, short or poor connection. The exact subfault definition can vary by manufacturer, so confirm the cause with testing.

Symptoms

  • Airbag (SRS) warning light on
  • Seat belt warning light or chime behaving incorrectly
  • Pretensioner may not deploy in a crash
  • Code returns after being cleared

Possible causes

  1. Faulty driver seatbelt pretensioner or buckle sensor
  2. Damaged, corroded or loose connectors in the SRS harness
  3. Open or shorted wiring under the seat or in the pillar
  4. Failed SRS control module
  5. Components incorrectly installed or connected after seat or interior work

How to diagnose

  1. Scan for codes with an SRS-capable tool and note any related faults
  2. Inspect the connectors under the driver seat and at the buckle for corrosion, bent pins or loose locks
  3. Find out whether the seat was moved or interior wiring was touched before the light came on
  4. Check the harness for chafing or pinching where it flexes
  5. Do not probe the squib circuit with a regular meter, as this could set off the device; use only the manufacturer-approved method
  6. Check battery voltage and the SRS module ground
  7. Clear the code and see if it returns
  8. If it returns, test the circuit per the wiring diagram with a load simulator and replace the failed part

Common fixes

  • Replace the driver seatbelt pretensioner or buckle assembly
  • Repair or replace the damaged harness or connector
  • Replace or reprogram the SRS control module
  • Clean and reseat the connections, then clear the code

Questions and answers

Can I drive with code B0079?

The car will run normally, but the driver seatbelt pretensioner may not deploy in a crash. Do not put off the repair for long.

Can I test the pretensioner circuit myself?

Visual checks of connectors are fine, but disconnect the battery and wait the time the manufacturer specifies first. Never measure the squib circuit without proper equipment because of the risk of accidental deployment.

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.