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P0415Secondary Air Injection System Switching Valve "B" Circuit Malfunction

The engine computer has detected an electrical fault in the control circuit for the secondary air injection switching valve on the second bank (Valve B).

Definition

On V-configuration engines with a dual-path secondary air injection system, a second switching (diverter) valve — Valve "B" — routes pump air into the bank 2 exhaust manifold during cold starts. The PCM monitors the Valve B solenoid control circuit and sets P0415 when it detects a general electrical fault: an open, a short, or an implausible driver state. The engine drives normally, but the MIL illuminates, bank 2 catalyst light-off slows, cold-start emissions rise, and the vehicle will fail an emissions inspection.

Common causes

  • Failed Valve B switching solenoid (open or shorted winding)
  • Corroded connector from moisture migrating through the AIR plumbing
  • Chafed or broken control wiring on the bank 2 side
  • Blown fuse on the solenoid supply circuit
  • Sticking or corroded valve from exhaust condensation
  • Faulty PCM driver (rare)

Common misdiagnoses

  • Air pump replaced when only the bank 2 switching valve circuit was faulty
  • Valve A replaced instead of Valve B (banks confused)
  • Bank 2 oxygen sensor replaced for cold-start signal complaints
  • Check valves replaced for a purely electrical code

Troubleshooting steps

  1. 1.Identify Valve B on the vehicle

    Consult the service information to confirm which physical valve serves bank 2 before testing, since swapped bank diagnosis is a common wasted repair.

  2. 2.Check supply voltage and fuse

    Verify ignition/battery voltage at the Valve B connector with the key on and confirm the AIR solenoid fuse is intact.

  3. 3.Measure solenoid resistance

    Ohm the solenoid and compare to spec (typically 20-100 ohms); OL means open, near 0 means shorted.

  4. 4.Test the control circuit

    With both ends disconnected, verify under 1 ohm continuity on the control wire to the PCM and no shorts to ground or power.

  5. 5.Command the valve and verify operation

    Energize the valve with a bidirectional scan tool and confirm it clicks and passes air; also check for water pooled inside the valve body.

  6. 6.Complete the AIR monitor

    After repairs, perform a cold-start drive cycle and confirm the secondary air monitor runs and passes.

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