Regal V6-173 2.8L (1988)
Coolant Temperature Sensor/Switch (For Computer): Description and Operation
PURPOSE
The coolant sensor is a thermistor (a resistor which changes value based on temperature) mounted in the engine coolant stream. This changing
resistance supplies the Electronic Control Module (ECM) with the engine coolant temperature data.
OPERATION
The ECM supplies a 5 volt signal to the coolant sensor through a resistor in the ECM and measures the voltage. The voltage will be high when the
engine is cold and low when the engine is hot. By measuring the voltage, the ECM knows the engine coolant temperature. Engine coolant
temperature affects most systems the ECM controls.
NOTES:
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A failure in the coolant sensor circuit should set either a Code 14 or Code 15. Once the trouble code is set, the ECM will use a default valve
for engine coolant temperature.
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Remember, these codes indicate a failure in the coolant temperature circuit, so proper use of the chart will lead to either repairing a wiring
problem or replacing the sensor to properly repair a problem.
