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Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the Q63 evaporative emission system leak detection pump.
  2. Service Mode active, verify that a test lamp illuminates between the voltage supply circuit terminal 3 and ground.
    • If the test lamp does not illuminate, test the voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal and the voltage supply circuit fuse is not open, test all components connected to the voltage supply circuit and replace as necessary.
  3. Connect a test lamp between the voltage supply circuit terminal 3 and the control circuit terminal 4.
  4. Command the Q63 evaporative emission system leak detection pump ON and OFF. The test lamp should respond to the command.
    • If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the K20 engine control module.
    • If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 engine control module.
  5. If all circuits test normal, test or replace the evaporative emission system leak detection pump.
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