Circuit Description
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The engine coolant temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. The engine control module (ECM) supplies 5 volts to the ECT signal circuit and supplies a ground to the low reference circuit. The ECM monitors the performance of the ECT sensor. If the ECM detects excessive noise or rapid fluctuations in the ECT signal, this DTC sets.
The following table illustrates the difference between temperature, resistance, and voltage:
| ECT | ECT Resistance | ECT Signal Voltage |
|---|---|---|
| Cold | High | High |
| Warm | Low | Low |