Conditions For Setting DTC
WARNING: This page is about a different car, the 2003 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
DTC P0443 will set if the EVAP purge solenoid feedback voltage is 2.6-4.6 volts, ECM pull-up voltage indicating an open circuit, when EVAP purge solenoid is commanded OFF and the condition exists for longer than 0.5 second.