Mitsubishi 1989-1993 GALANT Service Manual page 406

FUEL SYSTEM <DOHC>
OPERATION
The intake air temperature sensor functions to
l
convert the temperature of the air (intaken to the
engine) to voltage, and to input that voltage (as
signals) to the eingine control module. The en-
gine control module, based upon those signals,
then corrects the amount of fuel injection, etc.
The 5V power supply within the engine control
l
module is supplied, by way of the resistance
within the unit, to the intake air temperature
sensor; it passes through the intake air temper-
ature sensor, which is a type of resistor, and is
grounded at the engine control module.
TROUBLESHOOTING HINTS
Because the intake air temperature sensor detects
the temperature of the intake air in the air cleaner, it
indicates a temperature different than the tempera-
ture of the outside air when the engine is running.
INSPECTION
Using Scan tool
Function
Item No.
Data reading
13
HARNESS INSPECTION
< N o n - T u r b o >
<Turbo
<Turbo>
I
H a r n e s s fi
side
connector '-------
Data display Check conditions
Sensor de- Ignition switch: ON
Or, engine running
tection
Measure the power supply voltage.
. Ignition switch: ON
Check for continuity of the gl round
circuit of the intake air temperature
sensor.
. Connector: Disconnected
I I
Note that the resistance of the intake air
temperature sensor decreases when the
temperature of the intake air increases.
* The intake air temperature sensor terminal
voltage becomes higher when the resistance of
the intake air temperature sensor increases, and
becomes lower when the resistance decreases.
Consequently, the intake air temperature sensor
terminal voltage varies in accordance with the
temperature of the intake air, becoming lower
when the temperature of the intake air in-
creases.
Intake air temp.
At -20°C (-4°F)
At 0°C (32°F)
At 20°C (68°F)
At 40°C (104°F)
At 80°C (176°F)
Standard value
Repair the
harness.