ECT Sensor No.1 Inspection

Disconnect the negative battery cable.
Drain the engine coolant. (See COOLING SYSTEM SERVICE WARNINGS ).
Remove the battery. (See BATTERY REMOVAL/INSTALLATION [MZR 1.5] ).
Disconnect the ECT sensor No.1 connector.
Remove the ECT sensor No.1. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION ).
Place the ECT sensor No.1 in water with a thermometer, and heat the water gradually.

Measure the resistance between the ECT sensor No.1 terminals using an ohmmeter.

ECT SENSOR NO.1 SPECIFICATION

ECT (°C {°F})	Resistance (kilohms)
20 {68}	Approx. 2.45
80 {176}	Approx. 0.318

Fig 1: Identifying ECT Sensor No.1 Connector