Test Description

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

1. 2
   
   This step determines if the 5-volt reference is present.
2. 3
   
   This step checks the ground circuit.
3. 4
   
   This step determines if the problem is currently active by the scan tool displaying Last Test Failed. Do not proceed any further with this procedure if the scan tool does not display the term Last Test Failed. Duplicating the conditions in Freeze Frame/Failure Records can help create an active fault.
4. 5
   
   This step determines if a High Res signal is being sent to the PCM. See RPM VS HERTZ FOR HIGH RESOLUTION SIGNAL  table to compare the Hertz readings at different RPM. Use the Freeze Frame/Failure Records to help identify the RPM when the problem occurs.
5. 9
   
   The PCM supplies 5 volts on the signal circuit. This step determines if that voltage is present, not present, or too much voltage is present.
6. 13
   
   This step determines if the signal circuit is shorted to 5 volts. A normal high resolution signal circuit will have 3-5 mA. Any reading over 25 mA indicates a short to 5 volts.