What does it mean when the engine yellow light comes on in the car?

[DelIsaac]

The reasons for the engine yellow light coming on in the car: 1. Oxygen sensor failure, where the oxygen sensor is damaged or the sensor connector is damaged or loose, leading to a mixture that is too lean or too rich; 2. Airflow sensor failure, where the airflow sensor or its circuit malfunctions, causing the ECU to receive incorrect intake air signals, which prevents normal fuel control, resulting in a mixture that is too lean or too rich and the engine not functioning properly; 3. Spark plug carbon buildup, which can cause poor engine performance, leading to difficulties in starting, unstable idling, poor acceleration, backfiring during sudden acceleration, and abnormal exhaust emissions; 4. Engine knocking, where the engine inhales a mixture of fuel and air, and before the compression stroke reaches the intended ignition point, factors beyond control cause the mixture to ignite spontaneously. The resulting shockwave opposes the piston's movement, causing engine vibration, a phenomenon known as knocking, which manifests as weak car performance, excessive engine noise, and in severe cases, accompanied by knocking sounds from the cylinder.