ECT Sensor Resistance Inspection

WARNING: This page is about a different car, the 2009 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.

Disconnect the negative battery cable.
Drain the engine coolant. (See COOLING SYSTEM SERVICE WARNINGS [L5] .)
Remove the battery. (See BATTERY REMOVAL/INSTALLATION [L5] .)
Remove the ECT sensor. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION [L5] .)
Place the ECT sensor in water with a thermometer, and heat the water gradually.

Measure the resistance between the ECT sensor terminals A and B using an ohmmeter.

If not as specified, replace the ECT sensor. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION [L5] .)

SPECIFICATION

ECT (°C {°F})	Resistance (kilohms)
20 {68}	35.48-39.20
80 {176}	3.65-4 02

Fig 1: Identifying Engine Coolant Temperature Sensor Connector Terminals

Courtesy of MAZDA MOTORS CORP.