Engine Coolant Temperature (ECT) Sensor Inspection
WARNING: This page is about a different car, the 2006 Suzuki XL-7. However, it is still accessible from the selected car via links, so may be relevant.
Reference: ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL AND INSTALLATION
Immerse temperature sensing part of ECT sensor in water and measure resistance between sensor terminals while heating water gradually.
If measured resistance doesn't shown such characteristic as shown in the figure, replace ECT sensor.