What it means
This code identifies a fault associated with left side restraints sensor 1. The restraint control module sets it when it detects a problem with that sensor; the specific electrical or internal fault is identified by accompanying subfault information.
How it works
The restraint control module monitors left side restraints sensor 1 and its signal for side-impact detection. It stores B0091 when that sensor's circuit or signal fails a self-check; the accompanying subfault information identifies the fault type.
Common causes
Most likely first.
- Damaged sensor wiring or connector
- Faulty side restraints sensor
- Sensor power or ground fault
- Restraint control module fault
Symptoms
- Airbag warning light on
- Side airbag system may not respond as intended in a crash
How to diagnose it
- Read the restraint module's freeze-frame data and subfault details to confirm that the fault is for left side sensor 1 and identify the recorded condition.
- With the SRS system made safe according to the vehicle manufacturer's procedure, inspect left side sensor 1, its mounting area, connector, and wiring for damage, looseness, or corrosion.
- Check the sensor's power and ground circuits using the manufacturer's diagnostic procedure and specifications.
- Test the left side sensor 1 signal circuit for an open or short as specified; do not probe or apply power to SRS circuits with ordinary test equipment.
- If the circuit checks pass, test left side sensor 1 and the restraint control module as directed by the vehicle-specific procedure.
Common fixes
- Secure or repair the left side sensor 1 connector.
- Repair damaged wiring or restore the sensor's power or ground connection.
- Replace left side restraints sensor 1 if it fails the manufacturer's test or is damaged.
- Repair or replace the restraint control module only if its checks confirm an internal fault.
Can I keep driving?
The vehicle may be drivable, but side-impact restraint response on the left may be impaired while the SRS warning is on. Arrange prompt diagnosis and avoid relying on the system to protect occupants in a side crash.
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.