F 150 Heritage 4WD Pickup V8-5.4L SOHC VIN Z Bi-fuel (2004)
Malfunction Indicator Lamp: Description and Operation
Bi-Fuel CNG Models
MALFUNCTION INDICATOR LAMP (MIL)
Malfunction Indicator Lamp (MIL)
Alternative fuel diagnostics are automatic, active and continuous monitors of the bi-fuel system while the vehicle is operating in compressed natural gas
(CNG) mode. The system monitors the activity of various sensor 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) and the ALT fuel selector switch indicator will change from a steady on to an irregular flashing condition. If the fault condition
stops, the MIL will return to normal status after three trips and the fault code is stored in continuous memory for access during diagnostic procedures. If
the fault condition does not occur for forty trips, the fault code is erased.
