Engine Coolant Temperature Sensor: Inspection

Check that the engine coolant temperature sensor has no deformation, cracks or other damages.
Immerse the engine coolant temperature sensor and a thermometer in water.
CAUTION: Take care not to allow water to get into the engine coolant temperature sensor connector. Completely remove any water inside.

Fig 1: Checking Engine Coolant Temperature Sensor Deformation
Courtesy of SUBARU OF AMERICA, INC.
Raise water temperature gradually, measure the resistance between the engine coolant temperature sensor terminals when the temperature is 20°C (68°F) and 80°C (176°F).
NOTE: Agitate the water for even temperature distribution.

Fig 2: Measuring Resistance Between Engine Coolant Temperature Sensor Terminals
Courtesy of SUBARU OF AMERICA, INC.

RESISTANCE REFERENCE CHART

Water temperature	Terminal No.	Standard
20°C (68°F)	1 and 2	2.45±0.2 kΩ
80°C (176°F)	1 and 2	0.318±0.013 kΩ