The Engine Coolant Temperature sensor (ECT), located on the intake manifold of the engine, converts the temperature of the coolant in the engine to voltage, and inputs this voltage to the ECM. The ECM uses these signals to help it decide how to regulate the MFI system components.
| Fig. 1: The location of the Engine Coolant Temperature
(ECT) sensor — 3.0L and 3.5L engines
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| Fig. 2: The location of the Engine Coolant Temperature
(ECT) sensor — 2.4L engines
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Since the ECT is a type of resistor, the electrical current flowing through the sensor from and to the ECM is changed by the temperature of the coolant. The hotter the coolant becomes, the lower the resistance created by the ECT sensor.
If, during engine warm up, the fast idling speed is not correct, or black smoke is emitted, the problem is usually a malfunction of the ECT sensor.
