Missing or loose fuel cap
Incorrect fuel filler cap used
Fuel filler cap remains open or fails to close
Foreign matter caught in the fuel filler cap
EVAP canister or fuel tank leaks
EVAP system hose leaking
Fuel tank leaking
Engine Light ON (or Service Engine Soon Warning Light)
Possible a noticeable fuel odor caused by the release of fuel vapors
The evaporative system monitoring permits the detection of leaks in the evaporative system with a diameter of 0.02 inches and up. By means of a Diagnostic Module Tank Leakage (DMTL), an electrically actuated pump located at the atmospheric connection of the evaporative canister, a pressure test of the evaporative system is performed.
During the Reference Leak Measurement, the electrically actuated pump delivers through the reference restriction. The engine-management system measures the pump’s electrical current consumption in this section.
During the Leak Measurement, the electrically actuated pump delivers through the charcoal canister into the fuel-tank system. The pressure in the evaporative system may be up to 2.5 kPa depending on the fuel level in the tank. The engine-management system measures the pump’s electrical current consumption. A comparison of the currents of the reference leak measurement and the leak measurement is an indication of the leakage in the tank.