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Home >> Hummer >> 2010 >> H3 Base, Standard >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Controls And Fuel - 3.7L - DTC P1400 To DTC P2635 >> DTC P2440 >> Circuit/System Testing
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Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the Secondary Air Solenoid.
  2. Test for less than 5 Ω between the ground circuit terminal 4 and ground.
    • If greater than the specified range, repair the ground circuit for an open/high resistance.
  3. Connect a test lamp between the Air Solenoid ignition voltage circuit terminal 6 and ground.
  4. Ignition ON, command the Air Solenoid ON and OFF with a scan tool. The test lamp should respond to the scan tool commands.
    • If the test lamp is always OFF, test the ignition circuit for a short to ground, or an open/high resistance. If the circuit tests normal, replace the Air Solenoid relay.
    • If the test lamp is always ON, test the ignition circuit for a short to voltage. If the circuit tests normal, replace the Air Solenoid relay.
  5. Disconnect the Air hose/pipe from the Air Solenoid.
  6. Ignition ON, command the Air Pump ON with a scan tool. Verify airflow to the Air Solenoid.
    • If there is limited or no airflow to the Air Solenoid, inspect for the following:
      • Hoses/pipes for a restriction or blockage
      • Hoses/pipes for being disconnected
      • The Air Pump ground circuit for high resistance
      • The Air Pump ignition voltage circuit for high resistance
        • If a condition is located, repair as necessary.
        • If a condition is not located, and the AIR pump operates with no pressure change, replace the Secondary Air Injection Pump.
  7. If all circuits test normal, test or replace the Air Solenoid.
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