DTC will set when the following conditions are present:

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 1997 GMC Savana Special, 1997 GMC Savana Camper Special, 1997 GMC Savana, 1997 Chevrolet RV Cutaway, and 1997 Chevrolet Cutaway. However, it is still accessible from the selected car via links, so may be relevant.

Engine is running.
No TP sensor DTCs are set.
No IAC sensor DTCs are set.
No EGR DTCs are set.
Change in engine speed is less than 100 RPM.
Change in throttle position is less than 1.95 percent.
Change in EGR flow is less than 5 percent.
Change in IAC is less than 5 counts.
No change in brake switch status.
No change in clutch status (manual transmission).
No change in power steering switch status.
No change in A/C clutch status.
Conditions have stabilized for 2 seconds.
Conditions are met for 24 consecutive tests in a sample of 100 tests.
Change in MAP sensor is greater than .68 volt.