What it means
This code identifies a fault associated with the left frontal restraints sensor. 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 the left frontal restraints sensor and its electrical signal as part of frontal crash detection. It stores B0090 when the sensor signal or circuit fails a self-check; the accompanying subfault information identifies the fault type.
Common causes
Most likely first.
- Damaged sensor wiring or connector
- Faulty left frontal restraints sensor
- Sensor power or ground fault
- Restraint control module fault
Symptoms
- Airbag warning light on
- Frontal 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 see when the left frontal sensor fault occurred and what condition was recorded.
- With the SRS system made safe according to the vehicle manufacturer's procedure, inspect the left frontal sensor and its connector for impact damage, looseness, corrosion, or damaged wiring.
- Check the sensor's power and ground circuits using the manufacturer's diagnostic procedure and specifications.
- Test the sensor signal circuit for an open or short as specified; avoid probing or applying power to SRS circuits with ordinary test equipment.
- If the sensor and wiring pass their checks, follow the vehicle-specific procedure to evaluate the restraint control module.
Common fixes
- Secure or repair a loose or corroded left frontal sensor connector.
- Repair damaged wiring or restore a faulty sensor power or ground connection.
- Replace the left frontal restraints sensor 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 frontal airbag or restraint response may be impaired while the SRS warning is on. Arrange prompt diagnosis and avoid relying on the system to protect occupants in a 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.