What does it mean when the engine light is on?
2 Answers
The engine light may come on due to reasons such as poor quality or substandard gasoline. Below are some related explanations about the engine light being on: 1. Poor quality or substandard gasoline: Poor quality gasoline (e.g., containing excessive impurities, high gum content, or high sulfur content) not only leads to incomplete combustion of the air-fuel mixture in the cylinders, resulting in excessive carbon deposits, but also poses risks such as clogging the fuel system and corroding components (e.g., the fuel pump). This directly affects the normal concentration of the air-fuel mixture, ultimately causing the engine fault light to illuminate and accompanied by shaking. 2. Oxygen sensor malfunction: Generally, cars are equipped with two oxygen sensors, one before and one after the three-way catalytic converter. The front oxygen sensor detects the air-fuel ratio under different engine operating conditions, while the ECU adjusts the fuel injection amount and calculates the ignition timing based on this signal. Therefore, if the oxygen sensor is damaged or the sensor connector is damaged or loose, it can cause the air-fuel mixture to be too lean or too rich, leading to the illumination of the fault light.
Seeing the engine light come on while driving usually indicates that the vehicle's computer has detected a minor issue or a major problem. The most common causes are faulty sensors, such as an oxygen sensor detecting abnormal exhaust emissions exceeding standards, or spark plugs misfiring leading to uneven combustion. It could also be a vacuum leak affecting idle speed. My advice is not to panic but also not to ignore it—find a place to read the fault code as soon as possible. An OBD scanner costs just a few dozen dollars, and you can plug it in yourself to check the code. For example, P0420 indicates a catalytic converter issue that needs timely repair; otherwise, fuel consumption may spike and the engine could be damaged. Checking if the fuel cap is tightened might sometimes turn off the light, saving you a trip to the shop. Regular maintenance, such as changing the oil and air filter, can reduce such sudden occurrences. Cars, like people, need attention to signal light changes to prevent problems before they arise.
