B0091: Left Side Restraints Sensor 1
The airbag module has detected a fault with left side crash sensor 1.
High risk
Have it checked soon. Left side and curtain airbags may not deploy.
Short answer · Can I keep driving with B0091?
The car drives normally, but left side and curtain airbags may not deploy. Have it checked soon.
What does B0091 mean?
B0091 points to the first left side crash sensor, usually in the front door or the B-pillar. Water in the door often corrodes it.
What the car does when the code is set
The airbag warning light comes on. Airbags may deploy late or not at all in a crash.
How the system works
Crash sensors in the front, doors and pillars tell the airbag module how hard and from where the car is hit. The module decides from these signals which airbags to fire.
Common symptoms
Possible causes
Listed without ranking. The cause on your car depends on make, engine and mileage — see the maker notes below.
- Damaged or loose sensorCrash sensors sit in the front, doors and pillars and can be knocked loose.
- Wiring or connector faultCorrosion or water entry, especially in doors, breaks the signal.
- Previous accident repairSensors must be replaced after many collisions.
- Wrong part or missing codingSome sensors must be coded to the car.
- Airbag module faultPossible once sensors and wiring have been checked.
How it is diagnosed
- Think about recent repairsDoor, bumper or body repairs often disturb crash sensors.
- Look for water entryWet door panels or floors can corrode sensor connectors.
- Have the restraint system testedA workshop reads the airbag module and checks each sensor.Leave airbag system work to trained staff; parts can deploy with great force.
- Clear and retestAfter the repair, the code must be cleared and the warning light must go out.
Questions about B0091
Why does water in the door matter?
Many side sensors sit inside the door, where a failed seal lets water reach them.
Can I replace a crash sensor myself?
It is not recommended. Airbag parts need safe handling and sometimes coding.