Circuit/System Testing

Engine idling, command the engine speed up to 1,400 RPM, down to 600 RPM, up to 1,400 RPM with a scan tool. Verify that the engine speed is within 100 RPM of the commanded speed.

• If the engine speed parameter is above the commanded speed inspect for the following:

• The engine for vacuum leaks
• The throttle valve for the correct operation. A throttle valve that does not close correctly sets this DTC.
• The crankcase ventilation system for the correct operation. Inspect for the following conditions:
  • The correct positive crankcase ventilation (PCV) valve is used
  • The routing of the PCV system
  • Vacuum leaks in the PCV system

• If the engine speed parameter is below the commanded speed inspect for the following:

• Excess deposits in the throttle body
• A parasitic load on the engine. For example, a transmission condition, a belt driven accessory condition.