Test Description

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

1. 1
   
   The System Check MUST be performed before proceeding with this diagnostic test. Failure to perform the System Check will result in misdiagnosis.
2. 2
   
   With ignition on, with engine off, the PCM should continuously illuminate the MIL.
3. 3
   
   The scan tool will command BOTH the PCM and AF ECM to turn the MIL OFF.
4. 5
   
   This step checks if a PCM system failure is the cause of the inoperative MIL. The most likely cause of no MIL and a no-start is a loss of voltage to the PCM.
5. 7
   
   This step tests for an open MIL Input circuit. The PCM should always command the MIL ON when the ignition is ON and engine is OFF.
6. 8
   
   This step tests for an open MIL control circuit or IPC.