Mitsubishi 3000GT Service Manual page 197

ENGINE COOLANT TEMPERATURE SENSOR <Up to 1993 models>
OPERATION
The engine coolant temperature sensor converts the engine coolant temperature into a voltage and
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inputs it to the engine control module, which then controls the fuel injection rate and fast idle speed
when the engine is cold based on the input signal.
The 5 V power in the engine control module is supplied via a resistor in the module to the engine
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coolant temperature sensor. Through the sensor which is a kind of resistor, it is grounded in the
engine control module. The engine coolant temperature sensor resistor has the characteristic of decreas-
ing its resistance decreases as the coolant temperature rises.
The engine coolant temperature sensor terminal voltage increases or decreases as the sensor resistance
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increases or decreases. Therefore, the engine coolant temperature sensor terminal voltage changes
with the coolant temperature, decreasing as the temperature rises.
TROUBLESHOOTING HINTS
If the fast idle speed is inadequate or the engine emits dark smoke during engine warm up operation,
the engine coolant temperature sensor is often faulty.
MULTIPORT On-Vehicle Inspection of MFI
FUEL INJECTION - Components
Resistance
Coolant temperature
A Equipment side
connector
TSB
Revision
Output
voltage
Coolant temperature
152455
teniperaturesensor
1
1621008