Circuit Description

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.

The Evaporative Emission (EVAP) system is used to store fuel vapors as to reduce the amount of unburned fuel from escaping into the atmosphere. The EVAP purge solenoid is used to control the flow of fuel vapor from the EVAP canister to the intake manifold. The ECM controls the solenoid by supplying it ground whenever the EVAP system is in purge mode. Fuel vapors can be purged anytime the ECM is in closed loop and the vehicle is not in a deceleration. When the solenoid is commanded off (circuit not grounded), the voltage level at the ECM should be high (ignition voltage). When the driver is commanded on (circuit grounded), the voltage level at the ECM should be low. The ECM EVAP purge solenoid feedback circuit uses a pull-up voltage (2.6-4.6 volts), which allows the ECM to individually differentiate between an open, short to ground or short to voltage. DTC P0443 will set if the ECM detects an open EVAP purge solenoid control circuit when EVAP purge solenoid is commanded off when engine cranking/running.