Resistance Inspection

WARNING:

A hot engine can cause severe burns. Turn off the engine and wait until it is cool before removing the ECT sensor No. 1.

Disconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION .)
Remove the ECT sensor No. 1. (See Engine Coolant Temperature (ECT) Sensor Removal/Installation .)
Place the ECT sensor No. 1 in water with a thermometer, and heat the water gradually.

Fig 1: Placing ECT Sensor No. 1 In Water With Thermometer
Courtesy of MAZDA MOTORS CORP.
Measure the resistance between ECT sensor No. 1 terminals A and B.
- If not as specified, replace the ECT sensor No. 1. (See Engine Coolant Temperature (ECT) Sensor Removal/Installation .)

ENGINE COOLANT TEMPERATURE RESISTANCE SPECIFICATION

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

Fig 2: ECT Sensor Terminals Resistance Graph

Courtesy of MAZDA MOTORS CORP.