What are the symptoms of a faulty water temperature sensor?

[Lynda]

Automobile water temperature sensor failure symptoms: 1. Difficulty in starting the car When the water temperature sensor fails, it often displays the temperature signal of a hot car when starting a cold car. The ECU cannot obtain the signal to provide a rich mixture, and can only supply the engine with a lean mixture signal for a hot car, so the engine is difficult to start when cold; 2. The water temperature sensor is short-circuited or the circuit is short-circuited, and the water temperature gauge pointer directly points to the highest position; the water temperature sensor is short-circuited or the circuit is short-circuited, and the water temperature gauge pointer does not move no matter what; the water temperature sensor is wrapped with pollutants, and the water temperature detection is inaccurate; 3. Affects the EGR valve. The function of the water temperature sensor is to convert the cooling water temperature into an electrical signal. After inputting it into the ECU, it has: correct the fuel injection amount; increase the fuel injection amount when the temperature is low; correct the ignition advance angle; increase the ignition advance angle when the temperature is low, and delay it when the temperature is high to prevent detonation; affect the idle speed control valve; when the temperature is low, the ECU controls the idle speed control valve to act according to the water temperature sensor signal to increase the speed.