B0043: Third Row Left Frontal Stage 3 Deployment Control

What it means

The restraint control module monitors the stage 3 deployment circuit for the third-row left frontal airbag. It sets this code when it detects an electrical fault in that circuit, such as an open, short, or resistance outside its expected range.

At a glance

• Usually lights the airbag (SRS) or body-system warning light

How it works

The restraint control module monitors stage 3 of the third-row left frontal airbag's deployment circuit. B0043 sets when this particular stage 3 circuit has an electrical fault, such as an open, short, or resistance outside the expected range.

Common causes

Most likely first.

1. Open or high resistance in the stage 3 inflator circuit
2. Shorted or damaged wiring
3. Loose or corroded connector
4. Fault in the restraint control module

Symptoms

• Warning light or symbol related to the affected system
• Comfort or safety function impaired

How to diagnose it

1. Use an SRS-capable scan tool to capture B0043's subfault details and freeze-frame or event data before clearing it.
2. After powering down the vehicle as directed by the manufacturer, inspect the third-row left frontal stage 3 wiring and connectors for damage, corrosion, poor seating, or prior repairs.
3. Use the manufacturer's wiring diagram and SRS-safe test method to check the stage 3 circuit for an open or short.
4. Check stage 3 circuit resistance and terminal contact against the manufacturer's procedure and specification, without probing the inflator unless expressly instructed.
5. If the stage 3 circuit passes, follow the service diagnosis to isolate a faulty airbag module from a restraint control module fault.

Common fixes

• Repair damaged wiring in the third-row left frontal stage 3 circuit.
• Repair or reseat a loose or corroded stage 3 connector using the approved SRS procedure.
• Replace the airbag module if its stage 3 deployment circuit fails the manufacturer's test.
• Repair or replace the restraint control module if circuit and airbag-module checks pass and module testing confirms the failure.

Can I keep driving?

Stage 3 of the third-row left frontal airbag may not deploy as intended in a crash, so have the SRS fault diagnosed promptly and avoid that seating position until repaired. Do not handle or test airbag wiring except as directed by the manufacturer's safety procedure.