F 150 Heritage 4WD Pickup V8-5.4L SOHC VIN Z Bi-fuel (2004)
Malfunction Indicator Lamp: Description and Operation
Bi-Fuel LPG Models
MALFUNCTION INDICATOR LAMP (MIL)
Malfunction Indicator Lamp (MIL)
Alternative fuel diagnostics are automatic, active, and continuous monitors of the bi-fuel system when the vehicle is operating in liquefied petroleum gas
(LPG) mode. The system monitors the activity of system inputs and compares the values to calibrated reference criteria. If a signal does not satisfy the
reference criteria, a fault code is generated and stored. If the fault is of an emissions-critical nature, the system will illuminate the malfunction indicator
lamp (MIL). Additionally, the selector switch light will change from a steady on to an irregular flashing condition. If the fault condition stops, the MIL
will return to normal status after two trips and the fault code is stored for access during diagnostic procedures. If the fault condition does not occur for
forty trips, the fault code is erased. If a temperature-related fault occurs, the compuvalve will operate using a default value to protect the engine from
severe over or under fueling. The compuvalve will continue to use the default value until the next key off/ key on cycle.
