Monitor Description

The ECT sensor is used to monitor the engine coolant temperature. The ECT sensor has a thermistor that varies its resistance depending on the temperature of the engine coolant. When the coolant temperature is low, the resistance in the thermistor increases. When the temperature is high, the resistance drops. The variations in resistance are reflected in the voltage output from the sensor. The ECM monitors the sensor voltage and uses this value to calculate the ECT. When the sensor output voltage deviates from the normal operating range, the ECM interprets this as a fault in the ECT sensor and sets a DTC. Example:

If the sensor voltage output is more than 4.91 V for 0.5 seconds or more, the ECM determines that there is an open in the ECT sensor circuit, and sets DTC P0118. Conversely, if the voltage output is less than 0.14 V for 0.5 seconds or more, the ECM determines that there is a short in the sensor circuit, and sets DTC P0117.

If the malfunction is not repaired successfully, a DTC is set 0.5 seconds after the engine is next started. MONITOR STRATEGY

Related DTCs

P0115 P0117 P0118

ECT sensor range check (Fluctuating) ECT sensor range check (Low voltage) ECT sensor range check (High voltage)

Required Sensors/Components (Main)

ECT sensor

Required Sensors/Components (Related)

-

Frequency of Operation

Continuous

Duration

0.5 seconds

MIL Operation

Immediate

Sequence of Operation

None

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