B0021

Left Side Deployment Stage 1 Control

Moderate severity

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.

Common causes

Loose airbag connector under driver seat
One of the most commonly reported causes for this code — check this first.
high
Typical part cost: $170-1100
Wiring pinched in seat rail
A plausible cause — test and verify before replacing parts.
medium
Typical part cost: $170-1100
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First things to check

1Confirm the code with a scan tool and check for additional related codes.
2Inspect the relevant sensors, wiring, and connectors for damage or corrosion.

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Related codes

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Frequently asked questions

What does B0021 mean?

B0021 means "Left Side Deployment Stage 1 Control". It is a generic OBD-II code that points to a fault in the body.

What are the most common causes of B0021?

loose airbag connector under driver seat; wiring pinched in seat rail; side airbag module internal fault — these are the most commonly reported causes. Verify with a proper diagnosis before replacing parts, or use the Wrenchify app for a vehicle-specific diagnosis.

Can I keep driving with this code?

The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical. Use the Wrenchify app for a full diagnosis specific to your vehicle.

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