Test Description

The numbers below refer to the step number in the diagnostic procedures.

1. 2
   
   Other AIR DTCs should be diagnosed first if set. If HO2S voltage remains below 50 millivolts for approximately 5 seconds, the system is operating normally.
2. 4
   
   Listen for a running motor. Command both the ON and OFF states. Repeat the commands as necessary.
3. 5
   
   Listen for an audible click when the device operates. Command both ON and OFF states. Repeat the commands as necessary.
4. 6
   
   This step begins eliminating an airflow problem.
5. 9
   
   This step tests for a vacuum leak at the valve.
6. 10
   
   This step tests the operation of the valve.
7. 12
   
   This step tests the control circuit for operation.
8. 13
   
   This step bypasses the relay to test pump operation.
9. 15
   
   This step tests the control circuit for operation.
10. 18
    
    This step eliminates the relay and the control circuit as a cause for continuous pump operation.
11. 19
    
    This step tests the control circuit for operation.
12. 40
    
    The pump may have failed from another fault. Refer to step  18, if pump operates without a command.
13. 42
    
    If the HO2S voltage remains below 50 millivolts for approximately 5 seconds, the system is operating normally.