Conditions for Setting DTC
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2002 GMC Savana Special, 2002 GMC Savana Camper Special, 2002 GMC Savana, 2002 Chevrolet RV Cutaway, and 2002 Chevrolet Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
The voltage on wait to start lamp circuit is high, near battery voltage, test 1; or the voltage on wait to start lamp control circuit is low, near 0 volts, test 2.