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P0413Secondary Air Injection System Switching Valve "A" Circuit Open

The control circuit for the secondary air injection switching valve (Valve A) is electrically open, so the valve cannot be commanded.

Definition

The secondary air injection (AIR) system pumps fresh air into the exhaust during cold starts to speed catalyst light-off, and the PCM opens a vacuum or electric switching (diverter/combination) valve to route that air. The PCM monitors current through the Valve "A" solenoid driver circuit and sets P0413 when it detects an open — no current flow when the solenoid is commanded on. The engine typically drives normally, but the MIL illuminates, cold-start emissions rise, and the vehicle will fail an emissions inspection; a stuck-closed air path can also leave the air pump noisy or allow moisture to accumulate and damage the pump over time.

Common causes

  • Failed switching/diverter valve solenoid with an open winding
  • Corroded or unplugged connector at the valve (moisture intrusion is common in AIR systems)
  • Broken or chafed wire in the control circuit
  • Blown fuse feeding the solenoid supply
  • Water/corrosion damage inside the valve from exhaust condensation
  • Faulty PCM driver (rare)

Common misdiagnoses

  • Secondary air pump replaced when only the switching valve circuit was open
  • Check valve replaced for what is an electrical circuit code
  • Oxygen sensors replaced chasing cold-start lean/rich reports
  • PCM replaced before checking the solenoid fuse and connector

Troubleshooting steps

  1. 1.Check the solenoid fuse and supply

    Verify the AIR solenoid fuse is intact and that battery or ignition voltage reaches the valve connector with the key on.

  2. 2.Measure solenoid resistance

    Ohm the switching valve solenoid at its connector; an open (OL) reading confirms a failed winding, while a value in the typical 20-100 ohm range shifts suspicion to the wiring.

  3. 3.Inspect the connector for corrosion

    Open the valve connector and look for green corrosion or water intrusion — condensation migrating through AIR plumbing commonly ruins these connections.

  4. 4.Test the control circuit continuity

    With connectors unplugged, ohm the control wire from the valve to the PCM pin, expecting under 1 ohm.

  5. 5.Command the valve with a scan tool

    Use a bidirectional AIR system test to energize the valve and confirm an audible click and airflow change after repairs.

  6. 6.Verify the AIR monitor passes

    Run a cold-start cycle and confirm the secondary air monitor completes without resetting the code.

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