Engine Coolant Temperature (ECT) Sensor Inspection

1. Disconnect the negative battery cable. (See BATTERY REMOVAL/INSTALLATION .)
2. Drain the engine coolant. (See ENGINE COOLANT REPLACEMENT .)
3. Remove the battery and battery tray. (See BATTERY REMOVAL/INSTALLATION .)
4. Disconnect the ECT sensor connector.
5. Remove the ECT sensor. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION .)
6. Place the ECT sensor in water with a thermometer, and heat the water gradually.
7. 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 .)

ECT SENSOR SPECIFICATION

ECT (°C{°F})	Resistance (kilohms)
20 {68}	35.48-39.20
80 {176}	3.65-4.02

Fig 1: Engine Coolant Temperature Sensor Terminals

Courtesy of MAZDA MOTORS CORP.