Circuit Description
WARNING: This page is about a different car, the 2002 Pontiac Grand Am, 2002 Oldsmobile Alero, 2002 Chevrolet Monte Carlo, and 2002 Chevrolet Impala. However, it is still accessible from the selected car via links, so may be relevant.
An ignition voltage is supplied directly to the Evaporative Emission (EVAP) purge valve. The EVAP purge valve is Pulse Width Modulated (PWM). The control module controls the EVAP purge valve ON time by grounding the control circuit via an internal switch called a driver. The scan tool displays the amount of ON time as a percentage. The control module monitors the status of the driver. If the control module detects an incorrect voltage for the commanded state of the drive, DTC P0443 sets.