B0021
Left Side Deployment Stage 1 Control
The SRS module has detected a fault in the deployment control circuit for the left side (driver) airbag stage 1. Side impact protection on the driver side may be reduced.
- Check engine light: Not always
- Emissions related: No
- Repair difficulty: hard
Symptoms
- Warning light or symbol related to the affected system
- Comfort or safety function impaired
Common causes
Ordered by how often each turns out to be the cause.
- Loose airbag connector under driver seatCommon
- Wiring pinched in seat railPossible
- Side airbag module internal faultLess likely
Parts involved
- Driver Side Airbag
- Srs Control Module
- Srs Seat Wiring
B0021 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.