What it means
An open circuit has been detected in the deployment loop of the left curtain (head) airbag. Curtain protection on the driver side will not deploy.
How it works
The restraint control module monitors the deployment loop for the left curtain airbag, which protects occupants along the vehicle's left side. B0046 sets when it detects an open circuit in that loop, so the left curtain may not deploy in a crash.
Common causes
Most likely first.
- Broken wire in headliner
- Curtain airbag connector unseated
Symptoms
- Airbag warning light on
How to diagnose it
- Read the SRS code details and event data with a scan tool that accesses the restraint control module, and confirm whether B0046 is current or intermittent.
- With the vehicle powered down according to the manufacturer's SRS procedure, inspect accessible left curtain wiring and connectors for a disconnected plug, damaged wire, or signs of headliner or trim work.
- Use the manufacturer's wiring diagram to trace the left curtain deployment loop and check for an open using the specified SRS-safe method.
- Inspect relevant terminals for poor contact or corrosion and test continuity as directed by the manufacturer; do not measure across the inflator unless explicitly allowed.
- If the loop wiring and connectors pass, follow the service procedure to test the left curtain module and restraint control module.
Common fixes
- Reconnect a left curtain connector that is unseated, following the SRS safety procedure.
- Repair an open or damaged wire in the left curtain deployment loop using the manufacturer's approved method.
- Replace a left curtain module if its deployment loop fails the specified test.
- Repair or replace the restraint control module if the loop and curtain module pass and diagnosis confirms a module fault.
Can I keep driving?
The left curtain airbag may not protect occupants in a side impact or rollover, so arrange prompt repair and avoid carrying passengers beside the affected area until it is fixed. Do not disturb curtain-airbag wiring or trim without following the manufacturer's SRS precautions.
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.