Engine Coolant Temperature Sensor (Dohc) - Mitsubishi 1989-1993 GALANT Service Manual

FUEL SYSTEM <DOHC> - FUEL SYSTEM <DOHC> -
ENGINE COOLANT TEMPERATURE SENSOR ENGINE COOLANT TEMPERATURE SENSOR
connector
OPERATION
The engine coolant temperature sensor func-
l
tions to convert the barometric pressure to vol-
tage, and to input that voltage (as signals) to the
The engine control module, based upon those
signals, regulates the amount of fuel injection
and the fast-idling speed when the engine is
cold.
The 5V power supply within the engine control
l
module is supplied, by way of the resistance
within the unit, to the engine coolant tempera-
ture sensor; it passes through the engine
coolant temperature sensor, which is a type of
resistor, and is grounded at the engine control
module.
TROUBLESHOOTING HINTS
If, during engine warm-up, the fast-idling speed is
not correct, or black smoke is emitted, the problem
On-Vehicle Inspection of MFI Components On-Vehicle Inspection of MFI Components
Coolant temperature Coolant temperature
e t side Engine coolant temperature
o m p o n n
connector
,
Engine
control
module
l
is usually a malfunction of the engine coolant tem-
perature sensor.
TSB Revision
Coolant temperature Coolant temperature
s e n s o r
Note that the resistance of the engine coolant
temperature sensor decreases when the tem-
perature of the coolant increases.
The engine coolant temperature
voltage becomes higher when the resistance of
the engine coolant temperature sensor in-
creases, and becomes lower when the resist-
ance decreases. Consequently, the engine
coolant temperature sensor terminal voltage va-
ries in accordance with the temperature of the
coolant, becoming lower when the temperature
of the coolant increases.
sensor terminal