Engine Coolant Temperature (ECT) Sensor: Miata
- Coolant temperature sender is part of ECT sensor. Remove ECT sensor. ECT sensor is located on left side of engine. Place ECT sensor and thermometer in a container of water. Connect ohmmeter between ECT sensor terminals "A" and "B". See Fig 1 .
- Slowly heat water. Observe resistance reading at specified temperatures. See ENGINE COOLANT TEMPERATURE (ECT) SENSOR SPECIFICATIONS table. If resistance is not as specified, replace ECT sensor.
- To check coolant temperature sender portion of ECT sensor, measure resistance between ground and ECT sensor terminal "C". See Fig 1 . Resistance should be 160-230 ohms with sensor temperature at 122°F (50°C). Replace ECT sensor as necessary.
ENGINE COOLANT TEMPERATURE (ECT) SENSOR SPECIFICATIONS
| Temperature - °F (°C) | Ohms | |
|---|---|---|
| Miata | ||
| 68 (20) | 2270-2740 | |
| 176 (80) | 290-340 | |
| Millenia, MPV & Protege | ||
| 68 (20) | 2200-2600 | |
| 176 (80) | 290-340 | |
| 626 | ||
| 68 (20) | 35,500-39,200 | |
| 176 (80) | 7180-7920 | |