What Causes the Engine Malfunction Warning Light to Stay On?

[DelFernando]

Engine malfunction warning light stays on for the following reasons: 1. Poor combustion state: Poor engine combustion state is the main reason for the engine malfunction light to illuminate. In automotive design, to ensure the engine operates in good condition and maintains a normal working lifespan, an oxygen sensor is installed on the engine to monitor the combustion state. Once the engine combustion state is poor, it not only causes environmental pollution but also leads to fuel waste and excessive engine wear. 2. Poor fuel quality: The engine has specific requirements for fuel quality indicators, especially as regulations worldwide impose higher demands on engines, thus requiring higher fuel quality standards. In reality, some gas stations may not fully comply with these standards to provide fuel that meets the requirements of high-performance engines, which often results in the engine malfunction light coming on. 3. Dirty engine cylinders or carbon deposits: After a certain period of use, the engine interior inevitably accumulates carbon deposits. These deposits can alter the engine's design parameters and, due to their unstable nature and heat retention, can cause irregular engine ignition, leading to engine knocking.