Fuel Filler Cap: Description and Operation

WARNING: FUEL TANK MAY BE PRESSURIZED. TO REMOVE FUEL TANK FILLER CAP), ROTATE OVER ONE-HALF TURN COUNTERCLOCKWISE. IF FUEL TANK FILLER CAP IS VENTING FUEL OR A HISSING SOUND IS HEARD, WAIT UNTIL THE CONDITION STOPS BEFORE CONTINUING TO TURN THE FUEL TANK FILLER CAP. IF THESE PRECAUTIONS ARE NOT FOLLOWED, FUEL MAY SPRAY AND CAUSE PERSONAL INJURY.


Operation
Under normal operating conditions, the fuel tank filler cap operates as a check valve, allowing air to enter the fuel tank as fuel is used, while preventing fuel vapors from escaping the fuel tank through the fuel tank filler cap.

Features
The fuel tank filler cap is a sealed cap with a built-in pressure-vacuum relief valve and:

^ fuel system vacuum relief is provided after negative 1.7 kPa (0.25 psi).

^ provides pressure relief above 14 kPa (2 psi).

^ Fuel tank filler cap damage or contamination that stops the pressure vacuum from working may result in fuel tank damage.

^ Care should be taken to use a proper fuel tank filler cap in good working order.

^ The fuel tank filler cap is a threaded screw-on design with a pre-vent feature that allows the fuel tank to vent for the first three-quarter turn before unthreading.

^ All fuel tank filler caps are retained to the vehicle with a tether using the filler pipe-to-housing screw at the three to four o'clock position.