What Causes the Engine Yellow Light to Illuminate on the Car Dashboard?
1 Answers
There are two main reasons why the engine yellow light on the car dashboard illuminates. The first is when the vehicle performs a self-check after the power is turned on. The second is when the engine fault yellow light remains on after the car is started, which is the ECU alerting you to an engine issue. Below are the reasons for the yellow light illumination: 1. Sensor Issues: The sensors mentioned here include the coolant temperature sensor, crankshaft position sensor, air flow sensor, intake air temperature sensor, and oxygen sensor. When these sensors are damaged, have poor contact, or experience signal interruption, the car's ECU cannot accurately obtain engine data, which triggers the engine fault light. 2. Maintenance Issues: Poor engine maintenance is the most common cause of the engine fault light. Vehicles have specific maintenance cycles, and if the owner fails to adhere to them, combined with poor driving habits, it increases the engine's operational burden, eventually prompting the yellow light to illuminate as a warning. 3. Poor Combustion of Air-Fuel Mixture: Issues such as faulty spark plugs, defective ignition coils, malfunctioning fuel pumps, or clogged fuel lines can lead to poor combustion of the air-fuel mixture in the engine. Poor combustion results in engine carbon buildup or knocking problems, which are detected by the engine's oxygen sensor and reported to the ECU, naturally triggering the fault light as a warning.
