Ford Explorer, Руководство по техническому обслуживанию и ремонту

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FAILURE MODE EFFECTS MANAGEMENT (FMEM)
The engine controller assembly contains back−up programs which allow the engine to operate if a sensor
signal is lost. If a sensor input is seen to be out of range−either high or low−the FMEM program is used. The
processor substitutes a fixed value for the missing sensor signal. The engine will continue to operate, although
performance and driveability may be noticeably reduced. This function of the controller is sometimes referred
to as the limp−in or fail−safe mode. If the missing sensor signal is restored, the FMEM system immediately
returns the system to normal operation. The dashboard warning lamp will be lit when FMEM is in effect.
HARDWARE LIMITED OPERATION STRATEGY (HLOS)
This mode is only used if the fault is too extreme for the FMEM circuit to handle. In this mode, the processor
has ceased all computation and control; the entire system is run on fixed values. The vehicle may be operated
but performance and driveability will be greatly reduced. The fixed or default settings provide minimal
calibration, allowing the vehicle to be carefully driven in for service. The dashboard warning lamp will be lit
when HLOS is engaged. Codes cannot be read while the system is operating in this mode.
MALFUNCTION INDICATOR LAMP (MIL)
The CHECK ENGINE or SERVICE ENGINE SOON dashboard warning lamp is referred to as the
Malfunction Indicator Lamp (MIL). The lamp is connected to the engine control assembly and will alert the
driver to certain malfunctions within the EEC system. When the lamp is lit, the PCM has detected a fault and
stored an identity code in memory. The engine control system will usually enter either FMEM or HLOS mode
and driveability will be impaired.
The light will stay on as long as the fault causing it is present. Should the fault self−correct, the MIL will
extinguish but the stored code will remain in memory.
Under normal operating conditions, the MIL should light briefly when the ignition key is turned ON. As soon
as the PCM receives a signal that the engine is cranking, the lamp will be extinguished. The dash warning
lamp should remain out during the entire operating cycle.
Diagnostic Connector
To read Diagnostic Trouble Codes (DTC's) the test connector for the EEC system must be used. This
connector is known as the Assembly Line Diagnostic Link (ALDL) connector on vehicles with EEC−IV
ignition equipped engines, or the Data Link Connector (DLC) on all other models (EEC−V), is located in the
passenger compartment. It is attached either to the underside of the instrument panel, and is accessible from
the driver's side of the vehicle, or it is under the hood near the power distribution box.
The connector is trapezoidal in shape and can accommodate up to 16 terminals.
HOW TO USE THIS BOOK
582 FAILURE MODE EFFECTS MANAGEMENT (FMEM)