FAILURE MODE EFFECTS MANAGEMENT
FMEM mode allows system operation when sensors fail or transmit signals that are out of normal operating
range. During FMEM mode, PCM substitutes a mid-range signal for defective sensor while continuing to
monitor sensor. If faulty sensor signals return to normal operating range, PCM will use those signals.
Depending on specific failure, a fault code may be set in PCM memory.
HARDWARE LIMITED OPERATIONAL STRATEGY
If a number of system or sensor failures are present and PCM is not receiving enough information to operate,
PCM will switch to HLOS mode. PCM will output fixed values to allow operation of vehicle. Driveability
concerns will be present. PCM will not output diagnostic trouble codes in this mode.
ENGINE RPM/VEHICLE SPEED LIMITER
The Powertrain Control Module (PCM) will disable some or all fuel injectors whenever an engine RPM or
vehicle overspeed condition is detected. The purpose of engine RPM/vehicle speed limiter is to prevent damage
to vehicle powertrain. Vehicle will run rough, and PCM will store a continuous memory DTC P1270. When
overspeed condition is over, engine will return to normal operation. If necessary, clear DTC P1270 from PCM.
2003 Ford Pickup F150
2003 ENGINE PERFORMANCE Self-Diagnostics - CNG, Flex-Fuel & Gasoline