What causes the engine malfunction indicator light to come on?
2 Answers
Engine malfunction indicator light may come on due to poor engine combustion state, use of fuel that does not meet the requirements of high-performance engines, unclean engine cylinders, carbon deposits, etc. When the malfunction light comes on, inspection and repair are necessary. The illumination of the engine malfunction light does not necessarily mean the engine cannot operate. An engine is a machine capable of converting other forms of energy into mechanical energy, applicable both as a power generation device and referring to the entire machine including the power unit, such as gasoline engines, aircraft engines. Engine types include internal combustion engines, external combustion engines, electric motors, etc.
Last time I was on a long-distance drive, the warning light suddenly came on, which scared me into pulling over at a service area to check the manual. This yellow light is called the MIL (Malfunction Indicator Lamp), most commonly triggered by a dirty exhaust oxygen sensor giving a false alarm, especially in older cars using cheap gas from small stations. The sensor is located near the exhaust pipe, and long-term buildup of oil and grime due to high temperatures can affect its signal accuracy. Another possibility is a loose fuel tank cap causing vapor leakage, making the onboard computer think there’s a fuel system leak and triggering the light. Additionally, a dirty throttle body causing inaccurate air intake calculations or worn-out spark plugs leading to poor ignition and excessive emissions can also prompt the computer to alert. If the car isn’t shaking and can still drive, it’s likely a minor false alarm, but you should read the trouble codes as soon as possible to confirm.
