Diagnostic Aids

Check for the following conditions:

• A poor connection or damaged harness-Inspect ECM harness connectors for the following:
  • Backed out terminals
  • Improper mating
  • Broken locks
  • Poor wire to terminal connections
• Intermittent test-Monitor a scan tool or digital voltmeter connected between the related circuits while moving the connectors and harnesses. If the failure is induced, the voltage reading will change. This will help locate a circuit condition. Refer to the following:
  • Intermittent Conditions in Engine Controls - 1.6L (L91)