Iat Sensor; Idle Position Switch; Ap Sensor; Clutch Switch - Isuzu 4HL1 Workshop Manual

IAT Sensor

The IAT (intake air temperature) sensor is installed to
the intake air duct and the thermistor in the sensor
alters the resistance in response to the temperature
change. Higher intake air temperature provides smaller
resistance while lower intake air temperature provides
larger resistance. The ECM supplies 5 V to the IAT
sensor via pull-up resistance and calculates the intake
air temperature from the change in voltage and uses it
in fuel injection control and other control tasks. The
voltage is decreased when the resistance is small (the
temperature is high) while increased when the
resistance is large (the temperature is low).

AP Sensor

The AP (accelerator pedal position) sensor is installed
to the top of the accelerator pedal and supplies the
voltage signal that will change in response to
accelerator pedal angle to the ECM. The ECM
calculates the accelerator pedal position from the
voltage signal for use in fuel injection control and other
diversified control tasks.

Idle Position Switch

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The idle position switch is installed to the accelerator
pedal, and is turned off when the pedal is pressed and
turned on when the pedal is released. The ECM
receives the on/off signal from this idle position switch
for use in exhaust brake control, warm-up control, and
other control tasks.

Clutch Switch

The clutch switch is installed to the clutch pedal, and is
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turned on when the pedal is pressed and turned off
when the pedal is released. The VIM receives the on/
off signal from this clutch switch for use in exhaust
brake control and other control tasks.
Engine Control System 1A-13
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