DTC will test 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.

No TP sensor DTCs are set.
No ECT sensor DTCs are set.
ECT greater than 162°F (72°C).
IAT greater than -13°F (-25°C).
BARO is greater than 70 kPa (less than 10,300 ft.).
Vehicle speed is less than 2 MPH.
No VSS DTCs are set.
No MAP sensor DTCs are set.
System voltage greater than 10 volts but less than 18 volts.
Engine run time is greater than 30 seconds.
Throttle position is less than 1 percent.
All conditions are met for greater than 3 seconds.