Evaporative Emission System Operation

WARNING: This page is about a different variant/trim than selected.

The Evaporative Emission control system limits fuel vapors from escaping into the atmosphere. Fuel tank vapors are allowed to move from the fuel tank, due to temperature changes in the tank, through the evaporative emission vapor tube, into the evaporative emission canister. Carbon in the canister absorbs and stores the fuel vapors. The Q13 Evaporative Emission Canister Vent Solenoid Valve vents the excess vapors through the vent hose to the atmosphere. The Evaporative Emission Canister stores the fuel vapors until the engine is able to use them. At an appropriate time, the engine control module (ECM) will command the Q12 Evaporative Emission Purge Solenoid Valve On/Open and the G58 Evaporative Emission Purge Pump ON, allowing vacuum to be applied to the Evaporative Emission Canister. With the normally open Q13 Evaporative Emission Canister Vent Solenoid Valve OFF/Open, fresh air is drawn through the Q13 Evaporative Emission Canister Vent Solenoid Valve and the vent hose to the Evaporative Emission Canister. Fresh air is drawn through the Evaporative Emission Canister, pulling fuel vapors from the carbon. The air/fuel vapor mixture continues through the Evaporative Emission Canister Purge Tube and the Q12 Evaporative Emission Purge Solenoid Valve into the induction system to be consumed during normal combustion. The ECM uses several tests to determine if the evaporative emission system is leaking or restricted.