Engine Coolant Temperature (ECT) Sensor

Ensure ignition is off. Disconnect electrical connector from ECT sensor. The ECT sensor is located in engine coolant passage near cylinder head or thermostat housing. To verify wire colors for proper identification, see appropriate wiring diagram information in WIRING DIAGRAMS article.
NOTE: The ECT may be also identified using appropriate illustration in THEORY & OPERATION article.
Using ohmmeter, check resistance between ECT sensor electrical terminals. Resistance should be within specification at designated temperature. See Fig 1. Replace ECT sensor if resistance is not within specification.

Fig 1: Checking Engine Coolant Temperature Sensor