Vim; Check Engine Lamp (Mil); Dlc - Isuzu 4HL1 Workshop Manual

The ECM is installed in the inner part of the engine left
side cover. The ECM uses signals sent from diversified
sensors to control those systems directly related to the
engine, for example, fuel injection control, intake
throttle control, EGR control, and QWS control.

VIM

The VIM is installed inside the center console in the
cab, and transmits signals sent from diversified
switches and sensors and drives powertrain actuators
such as exhaust brake, relays, and warning lamps
according to the commands from the ECM.

DLC

DLC (data link connector) is installed to the dash side
pane of the driver's seat and acts as a communication
interface between external diagnostic tool and on-
board controllers. The DLC can also function as a
diagnostic switch and when DLC pins are shorted, this
diagnostic switch is turned on.
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Engine Control System 1A-15

CHECK ENGINE Lamp (MIL)

The CHECK ENGINE lamp (MIL) is built in the meter
panel and informs the driver of faulty status of engine
or associated systems. When the ECM detects a fault
by means of its diagnostic function, this CHECK
ENGINE lamp is turned on. After the diagnostic switch
is turned on (DLC pins are shorted), the CHECK
ENGINE lamp blinks to inform the mechanic of
detection of DTC.
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