P0412 OBD II Trouble Code Secondary Air Injection System Switching Valve A Circuit Malfunction

Detailed information on troubleshooting and repairing a P0412 DTC code which has to do with the switching valve circuit in the secondary air injection system. Also includes links to relevant forum topics on the code.

Symptoms of P0412 OBD II Trouble Code

  • MIL (Malfunction indicator lamp) illumination
  • Increase in tailpipe emissions
  • Engine running rich

Common Causes of P0412 OBD II Trouble Code

  • Short to ground on control circuit
  • Short to voltage on control circuit
  • Control circuit open due to damage, etc.
  • Open or short on battery feed circuit to solenoid
  • Open or short on battery feed to relay control circuit