2021 Mazda MX-5 Miata Club, Automatic TransFACTORY OEM SERVICE PROCEDURE

Resistance Inspection

WARNING:
  • When the engine is hot, it can badly burn. Turn off the engine and wait until it is cool before removing the ECT sensor.
  1. Disconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION .)
  2. Drain the engine coolant. (See ENGINE COOLANT REPLACEMENT .)
  3. Disconnect the ECT sensor connector.
  4. Remove the ECT sensor using the SST. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION .)
  5. Place the ECT sensor in water with a thermometer, and heat the water gradually.
    G13488463Courtesy of MAZDA MOTORS CORP.
  6. Measure the resistance between ECT sensor terminals A and B.

Specification (Reference) 

ECT (°C {°F}) Resistance (Kilohms)
20 {68} Approx. 2.45
80 {176} Approx. 0.318
G11274169Courtesy of MAZDA MOTORS CORP.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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