Airbags

B0039 — Second Row Right Frontal Airbag Stage 1 Deployment Control Fault

Severity: high Drive with care, to a shop

What B0039 means

The SRS control module detected a fault in the circuit that controls stage 1 deployment of the second-row right frontal airbag. Normally the module continuously monitors this circuit for correct resistance and continuity, and sends a firing current to the inflator during a crash. With this fault, it cannot be sure the airbag will deploy, so it turns on the SRS lamp.

Symptoms

  • SRS/airbag warning light on in the cluster
  • Warning light that comes and goes
  • Second-row right airbag may not deploy in a crash
  • Code returns after being cleared

Possible causes

  1. Damaged or corroded airbag wiring or connectors
  2. Loose or poor connection under the seat or in the pillar
  3. Faulty airbag inflator or related component
  4. Failed SRS control module
  5. Aftermarket accessories, seat covers or seat work that disturbed the wiring

How to diagnose

  1. Scan all SRS codes with a scan tool that supports airbags and note the freeze frame data
  2. Ask whether interior, seat or body work was done recently
  3. Disconnect the battery and wait as the manufacturer specifies, then inspect the circuit connectors and harness for damage, corrosion and chafing
  4. Check that the yellow SRS connectors are fully seated and the terminals are tight
  5. Check circuit resistance only with the scan tool or the approved procedure; never probe an airbag inflator with a regular meter
  6. Check battery voltage and the SRS module ground
  7. Clear the code and see if it returns; if it does, test the SRS module

Common fixes

  • Repair or replace damaged wiring and connectors in the airbag circuit
  • Replace the faulty airbag module or inflator
  • Replace the SRS control module and program it as required
  • Remove unsuitable accessories and restore the factory wiring

Questions and answers

What does B0039 mean?

It means a fault in the control circuit for stage 1 of the second-row right frontal airbag. The SRS module can't confirm that circuit is working.

Can I drive with B0039?

Yes, the car will run, but the airbag may not deploy in a crash. Get it fixed as soon as you can.

Can I just clear the B0039 code?

Clearing it only turns the light off for a while. If the cause remains, the code will return and the protection is still in doubt.

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.