DTC P0443: EVAP Purge Solenoid Control Circuit: Description
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2003 Pontiac Grand Prix, 2003 Pontiac Bonneville, 2003 Chevrolet Monte Carlo, 2003 Chevrolet Impala, and 2003 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.
An ignition voltage is supplied directly to Evaporative (EVAP) emission purge valve. EVAP purge valve is Pulse Width Modulated (PWM). Powertrain Control Module (PCM) controls EVAP purge valve on time by grounding control circuit via an internal switch called a driver. Scan tool displays amount of on time as a percentage. PCM monitors status of driver. DTC sets when control module detects an incorrect voltage for commanded state of driver. If the control module detect an incorrect voltage for the commanded state of the driver, this DTC sets.