AFT-of-Axle Fuel Tank

PURPOSE
The evaporative emission system prevents the escape of hydrocarbon emissions into the atmosphere when the engine is off by storing the fuel vapors in the Evaporative Emissions Canister (EVAP canister). The system also controls the purging of stored fuel vapors from the evaporative emissions canister to the engine when the vehicle is being operated.

OPERATION
Fuel vapors trapped in the fuel tank are vented through evaporative emission valves located on top of the fuel tank. They allow the fuel vapor to pass into an evaporative emission return tube to the evaporative emissions canister.

The fuel vapors are stored in the evaporative emissions canister mounted on the rear crossmember. when the vehicle is operated, fuel vapors are purged from the evaporative emissions canister into the engine by means of the evaporative emissions management valve.

COMPONENTS
An evaporative emission return tube extends from the evaporative emission valve to the evaporative emissions management valve located in the right front corner of the engine compartment, behind the engine cover. The evaporative emissions management valve will open and close to maintain the correct vacuum in the evaporative emission system. From the evaporative emissions management valve through the evaporative emission return tube, the fuel vapors travel to the engine, allowing the vapors to be purged from the evaporative emissions canister.

A fuel tank pressure sensor, located in the fuel tank, monitors vacuum levels in the evaporative emission system. If the vacuum level is too low or drops too rapidly, the fuel tank pressure sensor will signal the control module to set a diagnostic trouble code.





An evaporative emission test port is provided for access to the evaporative emission system for test purposes. It is attached to the transmission fluid fill tube and is equipped with a protective cap.