B0013

What it means

B0013 is the generic SAE J2012 code for a fault in the passenger knee bolster deployment control circuit, part of the supplementary restraint system (SRS). The airbag control unit tests the resistance and voltage of the knee airbag deployment loop (the squib and its wiring) during its self-test. It sets the code when it sees an open circuit, a short to ground or voltage, or a resistance outside the expected range. The exact fault type and the way the circuit is tested depend on the vehicle.

Symptoms

• Airbag or SRS warning light on the dashboard
• Warning light stays on after start-up instead of going out
• Passenger knee airbag may not deploy in a collision
• Other SRS codes stored alongside it
• Intermittent airbag light that comes and goes with seat or trim movement

Possible causes

• Damaged, pinched or corroded wiring or connector in the knee bolster airbag circuitlikely
• Poor connection at the airbag connector under the dash or behind the glovebox, including a loose or unlatched locking cliplikely
• Faulty knee airbag module or its initiator (squib) with out-of-range resistancepossible
• Wiring disturbed by a previous repair, trim removal or interior workpossible
• Water ingress or damp in the footwell or dash area affecting the connectorspossible
• Fault inside the airbag control unit's deployment driverrare

How to diagnose

1. Read all stored SRS codes and any freeze frame or status data, and note whether the fault is current or historic and which sub-fault type is reported.
2. Check for recent work in the dash, glovebox or passenger footwell, and for signs of water ingress or damage.
3. Make sure the battery has been disconnected and the manufacturer's waiting time observed before touching any SRS connector. Then visually inspect the knee bolster airbag wiring and connectors for damage, corrosion, bent pins or unlatched clips.
4. Check the airbag connector's shorting bar or locking mechanism is seated correctly, following the manufacturer's procedure.
5. Check the wiring continuity and for shorts to ground or voltage with the circuit disconnected from the airbag module and control unit. Never apply a test current to an airbag module, and use only the method the manufacturer specifies.
6. Use the manufacturer's procedure to view live SRS data and the loop resistance, if the vehicle supports it, and compare with the specification.
7. Substitute a known-good module or test equipment approved by the manufacturer only if the procedure allows it, to separate a module fault from a wiring fault.
8. After repair, clear the codes, cycle the ignition and confirm the warning light goes out and the fault does not return.

How to fix

• Repair or replace damaged wiring using the manufacturer's approved method, and avoid improvised splices in SRS circuits.
• Clean, reseat or replace the affected connector and make sure the locking clips are fully engaged.
• Replace the passenger knee airbag module if its resistance is out of specification or it is damaged.
• Dry out and repair any water ingress, and replace corroded connectors or wiring.
• Replace or repair the airbag control unit only if testing proves it is faulty, and carry out any coding or setup the manufacturer requires.

Can I keep driving?

Nearby codes

• B0012GenericPassenger Frontal Stage 3 Deployment Control
• B0018GenericCenter Frontal Stage 1 Deployment Control