B3A21 — Active Aerodynamic Feature Control Module B

B3A21: Active Aerodynamic Feature Control Module B — what it means, the affected system and what to check before replacing parts.

Meaning, symptoms, causes and checks

Active Aerodynamic Feature Control Module B. Source catalogue definition; confirm applicability using vehicle service information.

Affected system: Body

Also written as: B3A21-00, B3A2100 (some scan tools add the fault-type byte, e.g. -00).