Non-Monitored Circuits

Note: Diagnostic trouble codes may not be displayed for these conditions. However, problems with these systems may cause driveability problems and cause trouble codes to be set for other circuits or systems.

- For Example: A fuel pressure problem will not register a trouble code directly, but could cause a rich or lean condition. This could cause an oxygen sensor fault to be stored in the PCM.

1. Clogged Fuel Pump Inlet Filter, Clogged In-line Fuel Filter, or a Pinched Fuel Supply or Return Line

- These problems could result in a rich or lean condition causing an oxygen sensor trouble code to be stored in the PCM.

2. Inoperative Ignition Coil, Fouled or Worn Spark Plugs, Ignition Cross Firing, or Open Spark Plug Cables

3. Incorrectly Indexed Distributor, Timing Chain, Camshaft Sprocket and Crankshaft Sprocket

- These could result in a rich or lean condition causing an oxygen sensor trouble code to be set by the PCM.

4. Uneven, Low, or High Engine Cylinder Compression

5. Plugged, Restricted or Leaking Exhaust System

6. Clogged Fuel Injector, Stuck Injector Pintle, or Wrong Injector Installed

- These could result in a rich or lean condition causing an oxygen sensor trouble code to be stored in the PCM.

7. Excessive Oil Consumption

8. Clogged or Restricted Air Cleaner Inlet or Filter Element

9. Restricted, Plugged or Loaded Evaporative Purge Canister

10. Leaks or Restrictions In Control System Vacuum Circuits

- These could result in a MAP sensor trouble code being stored in the PCM.

11. Poor PCM System Ground

12. Spread or Damaged PCM Connector Pins