Shadow Convertible L4-153 2.5L SOHC Turbo (1991)
Coolant Temperature Sensor/Switch (For Computer): Description and Operation
Coolant Temperature Sensor (Typical)
This sensor is located in the thermostat housing, and is in the flow of engine coolant so that it can monitor the coolant temperature. This sensor is a
variable resistor whose resistance value is inversely proportional to the temperature of the engine (as the temperature of the engine increases, the
resistance value decreases).
The engine controller monitors the voltage drop across the coolant temperature sensor. As the coolant temperature varies, so will the voltage drop across
the sensor. The engine controller interprets these voltage drops to indicate one of many different scenarios possible, and once it receives these signals it
will do one or more of the following:
^
Control engine warm-up idle speed.
^
Increase the ignition advance when the engine is warming up.
^
Adjust the injector pulse width for the appropriate engine operating condition. The engine controller will increase the injector pulse
width when the coolant temperature is cold resulting in a richer air-fuel mixture.
^
Turn the radiator fan ON or OFF.
^
Control turbo boost
