P0412 — AIR System Switching Valve A Circuit

P0412: AIR System Switching Valve A Circuit — what it means, the affected system and what to check before replacing parts.

Meaning, symptoms, causes and checks

AIR System Switching Valve A Circuit. Basic catalogue definition; diagnostic details have not yet been reviewed.

Affected system: Powertrain

Symptoms

  • Engine warning, higher emissions or unstable idle.

Possible causes

  • Faulty switching valve, damaged wiring or corroded connector.

What to check

  • Inspect valve connections, wiring and circuit fuses.

Also written as: P0412-00, P041200, PO412 (some scan tools add the fault-type byte, e.g. -00).