Circuit Description

The Evaporative Emission (EVAP) system is used to store fuel vapors to reduce amount of unburned fuel from escaping into atmosphere. The function of the EVAP vent solenoid is solely for EVAP leak diagnostics. Outside air flows around the normally open valve (except during portions of EVAP diagnostics) through the EVAP canister to the fuel tank, allowing fuel tank to be at atmospheric pressure (about 101 kPa). PCM controls EVAP vent solenoid by controlling an internal driver that pulls the solenoid circuit to ground. The EVAP vent solenoid circuit is monitored for low and high voltage faults. DTC will set when EVAP vent solenoid is commanded off and feedback voltage at PCM is low.

DTC will set if EVAP vent solenoid is less than 1.25 volts when EVAP vent solenoid is commanded off. Diagnostic runs continuously with ignition on and EVAP vent solenoid commanded off.