Circuit Description

Engine Coolant Temperature (ECT) sensor is a thermistor that varies resistance based on temperature. As temperature of ECT sensor increases, resistance decreases. High temperature will result in a low signal voltage. ECT sensor value will be about 1.5-2.0 volts when engine is fully warmed.

Conditions required to set DTC are:

• Engine running for longer than two minutes.
• ECT sensor signal indicates 302°F (150°C), about 0.14 volts for 12 seconds, over a 25-second period.