Engine Coolant Temperature (ECT) Sensor Inspection
WARNING: This page is about a different car, the 2004 Suzuki XL-7 and 2004 Suzuki Grand Vitara. However, it is still accessible from the selected car via links, so may be relevant.
Immerse temperature sensing part of ECT sensor in water and measure resistance between sensor terminals while heating water gradually. If measured resistance doesn't show characteristics as shown in the figure, replace ECT sensor.