What Does It Mean When the Yellow Light in a Car Comes On?
1 Answers
The yellow engine light is referred to differently across various car brands, some call it the engine fault light, while others name it the exhaust system fault light, but the icon is universally consistent. When this light illuminates, it indicates a malfunction in the engine's exhaust monitoring system, commonly known as catalytic converter poisoning. Here are some related explanations about the engine fault light: 1. Poor gasoline quality: Filling up with low-quality gasoline at non-standard gas stations can lead to incomplete combustion of the air-fuel mixture during engine operation, triggering the engine fault light. While this does not affect driving safety, it can cause varying degrees of damage to the engine. 2. Oxygen sensor malfunction: Vehicles are equipped with two oxygen sensors, one before and one after the catalytic converter. The front oxygen sensor detects the air-fuel ratio under different engine conditions, and the ECU uses this signal to adjust fuel injection and calculate ignition timing. The rear sensor primarily monitors the performance of the catalytic converter. Therefore, damage to the oxygen sensor or its connector, or if it becomes loose, can result in a mixture that is too lean or too rich, causing the fault light to illuminate. 3. Air flow sensor malfunction: The air flow sensor, also known as the air flow meter, measures the amount of air intake and converts it into an electrical signal sent to the ECU. Based on the optimal air-fuel ratio, it indirectly informs the ECU how much fuel to inject. If the air flow sensor or its circuit malfunctions, the ECU will not receive the correct air intake signal, leading to improper fuel control and resulting in a mixture that is too lean or too rich, preventing the engine from operating normally.
