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ECT Sensor Resistance Inspection

  1. Drain the engine coolant. (See COOLING SYSTEM SERVICE WARNINGS [L3, AJ] ).
  2. Remove the ECT sensor (located above the starter).
  3. Place the ECT sensor in water with a thermometer, and heat the water gradually.
  4. Measure the resistance between the ECT sensor terminals A and B using an ohmmeter.
    • If not as specified, replace the ECT sensor.
    • If the ECT sensor is normal, but PID value is out of specification, perform the "Circuit Open/Short Inspection".

Specification 

WATER TEMPERATURE RESISTANCE CHART

Water temperature (°C {°F}) Resistance (kilohm)
20 {68} 35.48-39.20
70 {158} 5.07-5.60
80 {176} 3.65-4.02
Fig 1: Engine Coolant Temperature Graph
G04325163Courtesy of MAZDA MOTORS CORP.