What Happens When a Car's Water Temperature Sensor Fails?
2 Answers
1. When a car's water temperature sensor fails, it can manifest in the following aspects: 1. The water temperature gauge needle does not move: it points to the highest position. 2. Difficulty in cold starts: Due to the faulty water temperature sensor, the ECU receives a hot engine temperature signal during a cold start and cannot provide a rich mixture signal, resulting in a lean mixture being supplied to the engine. 3. Increased fuel consumption and unstable idle: Difficulty in acceleration, even when the throttle is fully pressed, the engine RPM does not increase. 2. Below is additional information: 1. Principle of the car's water temperature sensor: The electronic control unit measures the engine coolant temperature based on this change; the lower the temperature, the greater the resistance, and vice versa. The electronic control unit uses this change to measure the engine coolant temperature as a correction signal for fuel injection and ignition timing. 2. Understanding the car's operating state: The engine's water temperature can help understand the current operating state of the car, whether it is stopped or moving, or how long it has been running, etc.
Last time my car's coolant temperature sensor malfunctioned, and the entire driving experience was awful. After starting the engine, the temperature gauge on the dashboard either stayed completely still or fluctuated wildly, and the engine warning light came on. The worst part was driving in winter—the heating system barely blew any warm air, leaving me shivering. In summer, the cooling fan wouldn't engage, causing the engine temperature to spike quickly, making me constantly worry about overheating during long trips. The mechanic explained that this sensor controls the coolant temperature signal. Once it fails, the engine control unit misjudges the situation, causing the engine to operate in incorrect states, such as excessive heating or insufficient cooling. Over time, this could lead to piston deformation or cylinder head gasket failure. I rushed to the repair shop for a replacement, and it was fixed for a small cost. Now during maintenance, I always remind the technician to check for aging sensor wiring to avoid similar issues.
