Resistance Inspection

1. Disconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION .)
2. Drain the engine coolant. (See ENGINE COOLANT REPLACEMENT .)
3. Remove the ECT sensor No. 1. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION .)
4. Place the ECT sensor No. 1 in water with a thermometer, and heat the water gradually.
   Fig 1: Measuring Resistance Between ECT Sensor No. 1 Terminals A And B

   Courtesy of MAZDA MOTORS CORP.
5. 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 .)

Specification (Reference) 

Fig 2: ECT Sensor No. 1 Resistance Graph

Courtesy of MAZDA MOTORS CORP.