Coolant Temperature Sensor/Switch (For Computer): Testing and Inspection

There are two temperature sensors which work independently of one another in the temperature sensor housing.
1. With ignition off, disconnect multiple pin plug from ECU.
2. With temperature sensor wire connector attached, connect ohmmeter test leads across ECU connector terminals 12 and 23. Correct resistance, at varying temperature is as follows:
a. Temperature at 32°F; 4400--6800 ohms.
b. Temperature at 75°F; 1400--3600 ohms.
c. Temperature at 104°F; 900--1300 ohms.
d. Temperature at 140°F; 480--720 ohms.
e. Temperature at 176°F; 250--390 ohms.
3. If resistance values are not as specified, test again at sensor by connecting one ohmmeter lead to ground and the other to one sensor contact. If resistance values are now satisfactory, check wiring between sensor and ECU. If resistance values are not satisfactory, replace sensor.