F 150 Super Crew 2WD V8-5.4L Prop SOHC VIN Z (2003)
Alternative Fuel Selector Indicator: Description and Operation
ALT/GAS Switch, ALT/GAS Switch Light
The ALT/GAS switch permits the driver to select which fuel the vehicle will operate on. The ALT/GAS switch is located on the instrument panel.
The ALT/GAS switch only operates when the vehicle is at a stop with the ignition in the OFF position. If the switch is moved while the vehicle is
running, the gaseous fuel system will NOT automatically change fuel mode and no damage to the vehicle will occur.
Prior to starting the vehicle (with the ignition in the OFF position), determine which fuel you intend to use and press the ALT/GAS switch.
When the selector switch is placed in the GAS position, the engine will operate in the unleaded gasoline mode.
When the switch is placed in the ALT position the engine will operate in the gaseous fuel mode (it temperature and pressure conditions are correct),
running on LPG. A green indicator light will illuminate on the fuel selector switch to indicate that the vehicle is operating in the gaseous fuel mode.
The ALT/GAS switch sends a signal to the compuvalve requesting ALT fuel mode, when placed in the ALT position. If no signal is received by the
compuvalve, the system defaults to base gasoline mode. The ALT/GAS switch light is incorporated into the ALT/GAS switch. It is controlled by the
compuvalve and is illuminated when operating in ALT/FUEL mode. If an emission-critical Diagnostic Trouble Code (DTC) is recorded, the
ALT/GAS switch light will change from a steady on to an irregular flashing condition. If a communication fault arises the indicator will flash with a
steady pulse. Once the key is switched to ON, the switch will not change the fuel operating mode. The ALT/GAS switch light has the following status
modes:
-
OFF
-
ON STEADY
-
ON THEN OFF (Quickly or Slowly)
-
FLASHING (REGULAR OR IRREGULAR)
