What Are the Reasons for the Engine Yellow Light?

[JustinMarie]

Engine yellow light mainly indicates a fault in the car's engine. The reasons for the engine yellow light are as follows: Sensor Issues: Sensors include coolant temperature, crankshaft position, air flow, intake air temperature, oxygen sensors, etc. When these sensors are damaged, have poor contact, or signal interruption, the car's ECU cannot accurately obtain engine data, which will trigger the engine fault light. Oil Quality Problems: The oil quality here refers to both fuel and engine oil. The fuel used in cars generally has a specific grade, and engine oil can be semi-synthetic or fully synthetic. Manufacturers usually recommend which grade of fuel and type of engine oil to use. If the owner does not follow these recommendations, long-term use can cause engine wear, leading to the yellow light. Poor Combustion of Air-Fuel Mixture: Faults in the engine's spark plugs, ignition coils, fuel pump, or clogged fuel lines can all cause poor combustion of the air-fuel mixture. Poor combustion leads to engine carbon deposits or knocking issues, which are eventually detected by the engine's oxygen sensor and reported to the ECU, naturally triggering the fault light as a warning.