Engine - Coolant Temperature Sensor/Switch: Testing and Inspection

Water Thermosensor Testing:

1. Disconnect water thermosensor connector. Remove sensor from engine.
2. Place sensor in a container with water and a thermometer. Heat gradually.
3. Check sensor resistance with an ohmmeter:

COOLANT TEMP. RESISTANCE (K OHMS)

-20°C (-4°F) 14.5 - 17.8
20°C (68°F) 2.2 - 2.7
40°C (104°F) 1.0 - 1.3
60°C (140°F) 0.50 - 0.65
80°C (176°F) 0.29 - 0.35


4. If not as specified, replace sensor.
5. Install sensor with a new washer and torque to 25 - 29 Nm (18 - 22 ftlb).
6. Connect thermosensor connector.

Water thermosensor input voltage can be checked at ECU terminal 2Q with ignition switch "ON." At coolant temperature of 20°C (68°F), voltage should be approximately 2.5V. At operating temperature, voltage should be approximately 0.4V.

If terminal voltage is always approximately 0V or 5V, refer to Malfunction Code No. 09 under DIAGNOSTIC CHARTS and check for faulty sensor.