Esteem L4-1590cc 16L SOHC 0 MFI 16V (1995) - Engine Temperature Sensor Inspection
Engine Temperature Sensor: Testing and Inspection
Component Inspection
Immerse temperature sensing part of Engine Coolant Temperature (ECT)sensor in water (or ice) and measure resistance between sensor terminals
while heating water gradually. If measured resistance doesn't show such characteristic as shown in the above image, replace ECT sensor.