B0021 — Left Curtain Deployment Control 1

Left Curtain Deployment Control 1. Basic catalogue definition; diagnostic details have not yet been reviewed.

Affected system: Body

Symptoms

• Airbag or supplemental restraint warning light
• Passenger-airbag status may be incorrect
• One or more restraint functions may be disabled
• The vehicle may otherwise drive normally

Possible causes

• Loose or high-resistance restraint-system connector
• Damaged wiring, clock spring, seat harness, or deployment-loop connector
• Faulty airbag, pretensioner, occupant sensor, or restraint control module
• Stored crash event or configuration problem

What to check

• Record every restraint code and failure-type byte before disconnecting power
• Follow the manufacturer depowering and waiting procedure
• Inspect the named loop, connector, seat harness, and clock spring without probing an inflator
• Use approved simulators or diagnostic tools only where service information permits
• Restore power, clear the code, and verify the restraint warning lamp self-test
• Read the complete restraint-module code including its failure-type byte
• Inspect connectors and harness routing using the manufacturer safety procedure
• Test only with approved restraint-system tools and specifications

Also written as: B0021-00, B002100, BO021 (some scan tools add the fault-type byte, e.g. -00).