The fill valve receives fuel from the fill nozzle at the CNG fill station. The valve is located behind the fill door, under the left taillight assembly. The fill valve contains a filter element designed to trap contaminants. This filter must be periodically inspected and cleaned. Refer to Periodic Maintenance Inspection in Maintenance and Lubrication for service intervals. An O-ring in the fill valve opening seals the connection between the valve and the fill nozzle during refueling. This O-ring must be inspected at each fuel fill. The O-ring must be replaced if it is missing or damaged.

The fill line is constructed of two section of 3/8 inch 316 stainless steel joined at an O-ring face seal union. The sections connect the fill valve to the CNG fuel tank.

The CNG fuel tank is constructed of steel and wrapped in carbon fiber set in epoxy. The tank capacity is 26.1 liters (6.9 gallons gasoline equivalent) at 24 820 kPa (3,600 psi) and 21°C (70°F). The tank is located in the trunk compartment and is mounted in a two-piece bracket with two straps. A cover protects the tank in order to prevent damage from shifting cargo.

The high pressure lock-off is a normally closed solenoid-operated valve. The HPL is mounted on the end of the CNG fuel tank and is not serviceable separately from the tank. The AF ECU controls the HPL solenoid. The valve opens when the solenoid is energized. This allows fuel to flow to the high pressure regulator (HPR). The HPL is energized only when the engine is cranking or running. Anytime the engine is stopped (ignition ON or OFF), the HPL closes to shut off the fuel supply.

The CNG tank mounting bracket consists of a tank mounting frame weldment, two tank straps and two upper brackets. The tank mounting frame mounts in the trunk under the rear window shelf. The frame is bolted to the floor and the well of the trunk. The tank strap secure the CNG tank to the mounting frame. The upper brackets restrict movement of the tank frame assembly.

The CNG tank cover protects the tank from damage caused by shifting cargo in the trunk.

The CNG manual shut-off valve allows the fuel supply to be shut off for service or during an emergency. The valve has a red handle and is mounted below the left rear passenger door. Turning the handle one-quarter turn clockwise closes the valve. Turning the handle one-quarter turn counterclockwise opens the valve.

The fuel gauge receives a signal from the engine control unit (ECU) in order to display the CNG fuel level. The fuel pressure sensor and the fuel temperature sensor each output a voltage to the ECU. The ECU uses these voltages in order to calculate the CNG fuel level. The ECU then outputs a pulse-width modulated signal to the fuel gauge. This signal corresponds to the amount of fuel in the CNG fuel tank.

The FPS is mounted on the HPL. The FTS is an integral part of the HPL and is mounted inside the CNG fuel tank.

The fuel indicator lamp shows the operator which fuel the vehicle is using. When the fuel indicator lamp is off, the vehicle is operating on CNG. When the fuel indicator lamp is on, the vehicle is operating on gasoline.

The fuel gauge selector switch allows the operator to check the level of fuel in both the gasoline and the CNG fuel tanks. If the switch is pressed when the vehicle is operating on CNG, the fuel gauge will indicate the amount of fuel in the gasoline tank. If the switch is pressed when the vehicle is operating on gasoline, the gauge will indicate the amount of CNG in the fuel tank. During the fuel level check, the fuel gauge will display the fuel level for about ten seconds. The gauge will then return to its previous position. If the vehicle is moving, this feature will not operate.

Caution: Natural gas is stored under high pressure. If a leak occurs, the high pressure could cause a personal injury. In order to prevent Compressed Natural Gas (CNG) fuel leaks, always replace the CNG fuel system O-rings during service.

Caution: Replace damaged Compressed Natural Gas (CNG) fuel lines. Do not repair the CNG fuel lines. Attempting to repair damaged CNG fuel lines could result in a serious personal injury.

All the high and medium pressure fuel line connections are sealed with O-ring face seals (ORFS). Always replace the ORFS when a CNG fuel line union is disconnected for service. Verify that the O-ring is designed for CNG. Do not use a common automotive or plumbing O-ring. Lubricate the replacement O-ring with petroleum jelly or the equivalent.

High Pressure Lines -- 6.4 mm (¼ in) diameter constructed of stainless steel tubing with a pressure rating of 24 820 kPa (3,600 psi).

Medium Pressure Line -- 6.4 mm (¼ in) diameter constructed of stainless steel tubing and flex hose with a pressure rating of 1 380 kPa (200 psi).