Coolant temperature sensor (ECT)
Caution: Allow the engine to cool completely before beginning this procedure.
Warning. The coolant temperature sensor must be handled with great care, as damage to it will disrupt the operation of the entire injection system.
Removal
1. The coolant temperature sensor is a thermistor (a resistor whose resistance value changes in response to changes in temperature). Changing the resistance value directly affects the output voltage signal from the sensor to the ECM. As the sensor temperature increases, its resistance decreases, and vice versa. Failure of the coolant temperature sensor and its circuits will cause the corresponding fault code to be stored in the ECM memory (see paragraph 2).
2. Make sure the ignition key is in the OFF position.
3. Partially drain the coolant so that its level is below the coolant temperature sensor.
4. Disconnect the wiring connector and carefully unscrew the sensor (see figure 8.4,a,b).
Figure 8.4,a. Engine coolant temperature sensor (ECT) (shown by the arrow) in models produced before 2000.
Figure 8.4,b. Engine coolant temperature sensor (ECT) (shown by the arrow) in models produced since 2001.
5. Wrap the threaded part of the new sensor with Teflon sealing tape (FUM tape) to prevent coolant leaks and thread corrosion.
Installation
6. Installation of the coolant temperature sensor is carried out in the reverse order of its removal.