Resistance Inspection

1. Remove the ECT sensor. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION [AJ] ).
2. Place the ECT sensor in water with a thermometer, and heat the water gradually.
3. Measure the resistance between ECT sensor terminals A and B using an ohmmeter.
   • If the ECT sensor is okay, but the PID value is out of specification, perform the "Circuit Open/Short Inspection".
   • If not as specified, replace the ECT sensor. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION [AJ] ).
     Fig 1: Identifying ECT Sensor Connector Terminals

     Courtesy of MAZDA MOTORS CORP.

Measure the ECT sensor resistance. 

ECT sensor characteristics graph (reference) 

Fig 2: ECT Sensor Characteristics Graph

Courtesy of MAZDA MOTORS CORP.