The coolant temperature sensor is installed in the coolant line on the cylinder head and monitors the coolant temperature and sends a signal to the ECM. 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 ECM determines the coolant temperature from the voltage value of the sensor signal and sets the optimum richness of the working mixture when the engine warms up.
Examination
1. Remove the coolant temperature sensor from the intake manifold.
2. While heating the vessel with water and the sensor located in it, check its resistance.
Temperature | Resistance |
-30°С | 22.22-31.78 kΩ |
-10°С | 8.16-10.74 kΩ |
0°C | 5.18-6.60 kΩ |
20°C | 2.27-2.73 kΩ |
40°С | 1.059-1.281 kΩ |
60°С | 0.538-0.650 kΩ |
80°С | 0.298-0.322 kΩ |
90°С | 0.219-0.243 kΩ |
3. If the resistance of the sensor differs from the required one, replace the sensor.
Installation
1. Apply LOCTITE 962T or equivalent to the sensor threads.
2. Screw in the sensor and tighten to specification.
Tightening torque: 15–20 Nm
3. Connect the connector to the sensor.