What it means
This code identifies a fault associated with the third row left side airbag deployment control. The restraint control module sets it when it detects a problem in that deployment control; the exact fault is specified by accompanying subfault information.
How it works
The restraint control module monitors the deployment control for the third-row left side airbag. It sets B0040 when it detects a fault in that control, while accompanying subfault information identifies the particular electrical problem.
Common causes
Most likely first.
- Third row airbag wiring or connector fault
- Open or shorted deployment circuit
- Faulty side airbag module
- Restraint control module fault
Symptoms
- Airbag warning light on
- Third row left side airbag may not deploy in a crash
How to diagnose it
- Read the restraint-system codes and freeze-frame or event data with a scan tool that can access the restraint control module, and record the subfault details before clearing anything.
- With the vehicle safely powered down according to the manufacturer's service procedure, inspect the third-row left side-airbag wiring and connectors for damage, looseness, corrosion, or signs of prior repairs.
- Use the manufacturer's wiring diagram to identify the deployment-control circuit and check it for an open or short using the prescribed SRS-safe test method.
- Check the circuit and connector terminals for high resistance or poor contact using the manufacturer's procedure and specification.
- If the wiring and connections pass, follow the service procedure to determine whether the third-row left side-airbag module or restraint control module is at fault.
Common fixes
- Repair damaged wiring in the third-row left side-airbag deployment circuit.
- Correct a loose, corroded, or damaged connector using the manufacturer's SRS repair procedure.
- Replace the third-row left side-airbag module if testing identifies it as faulty.
- Repair or replace the restraint control module only if the circuit and airbag module test correctly and the prescribed diagnosis confirms a module fault.
Can I keep driving?
Treat the airbag warning as a sign that third-row left side protection may be unavailable in a crash; arrange diagnosis promptly and avoid carrying passengers in that seating area until repaired. Do not probe or handle airbag wiring unless following the manufacturer's SRS safety procedure.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.