Circuit/System Description

WARNING: This page is about a different car, the 2009 Cadillac DTS. 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) canister purge solenoid valve. The control module controls the EVAP canister purge solenoid valve ON by grounding the control circuit by means of an internal switch called a driver. The control module monitors the status of the driver. The EVAP canister purge solenoid valve is pulse width modulated (PWM). The scan tool displays the amount of ON time as a percentage.

Battery voltage is supplied to the EVAP canister vent solenoid valve. The control module grounds the EVAP canister vent solenoid valve control circuit to close the valve by means of an internal switch called a driver. The control module monitors the status of the driver. The scan tool displays the commanded state of the EVAP canister vent solenoid valve as ON or OFF.