VCM will run EGR tests when 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.

No TP sensor DTCs are set.
No MAP sensor DTCs are set.
No VSS DTCs are set.
No IAT sensor DTCs are set.
No ECT sensor DTCs are set.
No IAC DTCs are set.
No linear EGR pintle position DTCs are set.
No transmission DTCs are set.
No HVAC DTCs are set.
Engine coolant temperature is greater than 172°F (78°C).
Baro is greater than 70 kPa (less than 10,3000 ft.).
Vehicle speed is greater than 30 MPH.
AC clutch status is unchanged.
Transmission is in locked or unlocked stage (stable).
No misfire DTCs are set.
Engine speed is 1000-1600 RPM.