Diagnostic Aids

Perform this test when instructed during QUICK TEST or if directed by other test procedures. Only use this test to diagnose the following:

• HO2S and sensor connection.
• Vacuum systems.
• Fuel injector and/or fuel injector circuitry.
• Powertrain Control Module (PCM).
• Electrical circuits (HO2S, HO2S GND, INJ 1-6, VPWR and SIG RTN).

To prevent replacement of good components, be aware, the following non-EEC areas may be cause of driveability concerns:

• Ignition system.
• Faulty evaporative emission system.
• EGR and/or PCV system.
• Air intake system.
• Engine oil contamination.
• Fuel system.
• Exhaust system leaks or restriction.
• Engine cooling system.