Fuel Tank Filler Pipe Cap

Fuel Filler Cap:

IMPORTANT: Replace the fuel filler cap with a cap that meets OEM specifications. Failure to use the correct fuel filler cap can result in the incorrect operation of the fuel delivery system.

The fuel filler cap is a pressure-vacuum type. A built-in torque-limiting device prevents over-tightening and, eliminates the escape of fuel vapors. In order to install the fuel cap, turn the cap clockwise until a clicking noise is heard. This indicates that the cap is seated.

A vacuum relief valve is incorporated into the fuel filler cap. The relief valve opens in order to relieve any vacuum pressure that is created within the fuel tank. This only occurs when the vacuum within the tank becomes excessive.

A pressure relief valve is also located in the fuel filler cap. If the pressure of the fuel vapor within the tank exceeds system's specification, the pressure relief valve opens. When the pressure relief valve opens, excess pressure is vented to the atmosphere.




The fuel level sensor (1) is located in the fuel tank (3) and is part of the fuel sender assembly (4). The fuel level sensor consists of a float, a float arm, and a variable resistor. The fuel level is measured by the position of the float in the fuel tank. The fuel level sensor indicates the position of the float to a gauge in the Instrument Panel (IP) cluster and to the powertrain control module. When the fuel level changes, the float position changes. The change in the float position increases or decreases the resistance reading of the variable resistor. The change in the resistance causes a change in the indicated fuel level. The PCM uses the signals from the fuel level sensor in order to determine when to perform certain diagnostic procedures on the EVAP system.