What are the symptoms of a faulty Buick Excelle coolant temperature sensor?

[Stuart]

The symptoms of a faulty Buick Excelle coolant temperature sensor are: 1. The engine is difficult to start when cold, with unstable idle speed, and may experience misfires or cylinder cutouts; 2. Acceleration becomes difficult, with no increase in RPM when the accelerator pedal is pressed, accompanied by black smoke and abnormal noises from the muffler. The function of the coolant temperature sensor is to convert the coolant temperature into an electrical signal, which is then input to the ECU to adjust the fuel injection quantity. During cold conditions, it increases fuel injection and adjusts the ignition timing advance. At low temperatures, it advances the ignition timing, while at high temperatures, it retards the timing to prevent knocking. It also affects the idle control valve, with the ECU controlling the idle control valve based on the coolant temperature sensor signal to increase RPM during cold starts. The Buick Excelle is a compact car under SAIC-GM Buick. Taking the 2020 Excelle 15N Manual Elite as an example, it features a 4-door, 5-seat sedan structure, a 40-liter fuel tank capacity, and a curb weight of 1070kg.