Diagnostic Aids
WARNING: This page is about a different car, the 2002 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
If a fuel trim, H02S, misfire, system voltage, throttle actuator or TP sensor DTC is also set, diagnose that DTC first. See DIAGNOSTIC TROUBLE CODE DEFINITIONS .
Verify the ECM ability to control engine speed by using the scan tool to perform the ENGINE SPEED CONTROL special function. The test will allow the RPM to be raised or lowered in increments of 25, 100 and 500 RPM. Compare the actual ENGINE SPEED to the DESIRED IDLE SPEED. Both should be within 100 RPM of each other.