The coolant temperature sensor is installed in the cylinder head and monitors the coolant temperature and sends a signal to the ECU. A thermistor is used as a sensor, which is sensitive to temperature changes.
The electrical resistance of the thermistor decreases as the temperature increases. The ECU senses the engine temperature from the output voltage of the sensor and provides the optimum air/fuel ratio when the engine is cold.
Examination
1. Remove the sensor from the cylinder head.
2. While heating the vessel with water and the sensor located in it, check its resistance.
Coolant temperature sensor
Temperature | Resistance, kOhm |
–20°C | 14,13–16,83 |
0°C | 5,79 |
20°C | 2,31–2,59 |
40°C | 1,48 |
60°C | 0,586 |
80°C | 0,322 |
Coolant temperature gauge
Temperature | Resistance, Ohm |
60°C | 125 |
85°C | 42,6–54,2 |
110°C | 22,1–26,2 |
125°C | 15,2 |
3. If the resistance of the sensor differs from the required one, replace the sensor.
Installation
1. Apply THREEBOND TB 2403 or equivalent to the sensor threads.
2. Screw in the sensor and tighten to specification. Tightening torque: 20–40 Nm.
3. Connect the connector to the sensor.