Resistance Inspection

WARNING:

When the engine is hot, it can badly burn. Turn off the engine and wait until it is cool before removing the ECT sensor.

Disconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION .)
Drain the engine coolant. (See ENGINE COOLANT REPLACEMENT .)
Disconnect the ECT sensor connector.
Remove the ECT sensor using the SST. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION .)
Place the ECT sensor in water with a thermometer, and heat the water gradually.

Courtesy of MAZDA MOTORS CORP.
Measure the resistance between ECT sensor terminals A and B.
- If not as specified, replace the ECT sensor. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION .)

Specification (Reference)

ECT (°C {°F})	Resistance (Kilohms)
20 {68}	Approx. 2.45
80 {176}	Approx. 0.318

Courtesy of MAZDA MOTORS CORP.