B0043

What it means

B0043 is the SAE generic code for a fault in the deployment control circuit for the third row left frontal restraint, stage 3. The SRS control unit runs a self-test on the squib (igniter) circuit and has seen a resistance, voltage or continuity reading outside the expected range, such as an open circuit, short or unexpected resistance. Which restraint this circuit feeds, and whether it is fitted at all, depends on the model and seating layout, so check the manufacturer wiring information.

Symptoms

• Airbag or SRS warning light on the dashboard
• SRS light stays on after start-up rather than going out after its self-check
• Third row restraint may not deploy in a crash while the fault is present
• Intermittent SRS light, often after the seats have been moved or folded
• Other SRS codes stored alongside it
• Car may fail an inspection because of the SRS warning

Possible causes

• Damaged, pinched or chafed wiring to the third row restraint, often where it passes seat mounts, folding mechanisms or trimlikely
• Poor connection at the squib or restraint connector, or at the yellow SRS connector under the seat or in the trim, such as corrosion, bent pins or a loose locklikely
• Faulty restraint component or squib with resistance out of rangepossible
• Wiring or connector disturbed after seat removal, trim work or earlier accident repairpossible
• Water ingress or corrosion in the connectors or wiring in the rear floor or trimpossible
• Fault inside the SRS control unitrare

How to diagnose

1. Read all stored and pending SRS codes with a scan tool that supports the SRS module, and record any freeze frame or status data
2. Check whether the code is current or historic, and whether other SRS or seat-related codes are present, to narrow down the circuit
3. Look up the model wiring diagram to confirm what this circuit feeds and where its connectors are
4. Visually inspect the third row seat area, trim and wiring for damage, crushed looms, water ingress and signs of previous repair
5. Make sure the battery is disconnected and the stated wait time has passed, then inspect the SRS connectors for corrosion, bent pins and correct seating
6. Test the circuit only using the manufacturer's SRS procedure, and never probe squib circuits with a test lamp or an unsuitable meter
7. Check for correct resistance and for shorts to ground or voltage in the harness, following the manufacturer's procedure
8. Clear the code after the repair and confirm it does not return after a function test and road test

How to fix

• Repair or replace the damaged section of wiring, using the approved method for SRS circuits
• Clean, reseat or replace faulty connectors and terminals, and secure the loom so it cannot be pinched or stretched
• Replace the faulty restraint component or squib if testing shows it is out of specification
• Dry out and repair any water ingress, and replace corroded connectors
• Replace or have the SRS control unit checked only once wiring and components have been proven good, following the manufacturer's procedure

Can I keep driving?

Nearby codes

• B0042GenericThird Row Left Frontal Stage 2 Deployment Control
• B0048GenericThird Row Right Side Airbag Deployment Control