DTC will set when the following conditions are present:

WARNING: This page is about a different car, the 1997 GMC Savana, 1997 Chevrolet Chevy Van, and 1997 Chevrolet Chevy Express. However, it is still accessible from the selected car via links, so may be relevant.

Purge solenoid diagnostic vacuum switch DTC is not set.
No IAC DTCs are set.
No MAP sensor DTCs are set.
No TP sensor DTCs are set.
No EGR DTCs are set.
BARO is greater than 75 kPa.
Engine coolant temperature is less than 230°F (110°C).
Power-up intake air temperature is greater than -.4°F (-18°C).
Intake air temperature is less than or equal to 194°F (90°C).
Change in engine coolant temperature/intake air temperature is less than or equal to 194°F (90°C).
Purge DC is greater than or equal to 90 percent.
MAP is greater than or equal to 20 kPa, but less than or equal to 80 kPa.
Throttle position is greater than or equal to 5 percent, but less than or equal to 60 percent.
Engine speed is greater than or equal to 800 RPM, but less than or equal to 3000 RPM.