Introduction to the reasons for the engine check light illuminating: 1. Sensor issues. The sensors mentioned here include coolant temperature, crankshaft position, air flow, intake air temperature, oxygen sensors, etc. When these sensors are damaged, have poor contact, or experience signal interruption, the car's ECU cannot accurately obtain engine data, which will cause the engine check light to illuminate. 2. Maintenance issues. Poor engine maintenance is the most common cause of the engine check light illuminating. 3. Fuel and oil quality issues. This includes both fuel and engine oil. The fuel added to a car usually has a specific grade, and engine oil can be semi-synthetic or fully synthetic. Manufacturers generally recommend which grade of fuel and type of oil to use. If the owner does not follow these recommendations, prolonged use can lead to engine wear. 4. Poor combustion of the air-fuel mixture. Faults in the engine's spark plugs, ignition coils, fuel pump, or clogged fuel lines can all cause poor combustion of the air-fuel mixture. Poor combustion leads to engine carbon buildup or knocking issues, which are eventually detected by the oxygen sensors in the exhaust system. After being reported to the ECU, the engine check light will illuminate as a warning. 5. Air intake issues. The engine requires air intake during combustion, and the air filter plays a crucial role in this process. If the car's air filter is dirty and not cleaned regularly, it can affect the air intake. Prolonged neglect can lead to clogging, and severe cases will cause the engine check light to illuminate. 6. False alarms. Driving on bumpy roads, tampering with certain engine connectors, or temporary signal interruptions in the ECU can all cause the engine check light to illuminate. However, these issues can usually be resolved by visiting a 4S shop to clear the fault codes with a diagnostic tool.
