B0099: Rollover Sensor
The airbag module has detected a fault with the rollover sensor.
High risk
Have it checked soon. Curtain airbags and pretensioners may not fire in a rollover.
Short answer · Can I keep driving with B0099?
The car drives normally, but curtain airbags and pretensioners may not fire in a rollover. Have it checked soon.
What does B0099 mean?
B0099 points to the sensor that detects a rollover. In many cars it is built into the airbag module.
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 B0099
Is the rollover sensor a separate part?
Sometimes; in many cars it is inside the airbag module, which is then replaced or repaired.
Can I replace a crash sensor myself?
It is not recommended. Airbag parts need safe handling and sometimes coding.