The engine malfunction indicator light may come on due to the following 7 main reasons: Sensor failure: 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 vehicle's ECU cannot accurately obtain engine data, which will trigger the engine malfunction light. Fuel quality issues: If fuel and engine oil are not added according to the manufacturer's requirements, it may cause engine wear and trigger the warning light. Poor combustion of air-fuel mixture: Poor combustion can lead to engine carbon buildup or knocking. When detected by oxygen sensors and reported to the ECU, the malfunction light will illuminate as a warning. Spark plug failure, ignition coil failure, fuel pump failure, or fuel line blockage can all cause poor combustion of the air-fuel mixture. Turbocharging issues: Problems with the intake boost piping or turbocharger can also trigger the engine warning light. The most common issue is turbocharger damage, often accompanied by oil leaks, excessive oil consumption, reduced power, metallic noises, or blue/black smoke from the exhaust. Intake problems: If there are issues with the vehicle's air intake, it may cause engine piping blockage, and in severe cases, trigger the warning light. A dirty air filter that hasn't been cleaned regularly can lead to intake problems. Exhaust system issues: Exhaust faults can also illuminate the engine light. Common causes include rear oxygen sensor failure, catalytic converter issues, or exhaust camshaft and bearing failures. Using leaded gasoline, lead/silicon-containing lubricant additives, physical damage to the catalytic converter, or fuel system malfunctions can all contribute to catalytic converter problems. Anti-theft system malfunction: If the electronic anti-theft system fails or if there's incompatibility between the anti-theft controller and engine ECU, the system may prevent normal engine operation while illuminating the warning light. When the engine malfunction light comes on, follow these steps: First check if the engine is operating normally - observe for shaking, black smoke emissions, etc. If present, avoid restarting the engine. Particularly note: Never restart if the red warning light is on. If the engine can be started, turn off the ignition for 5-10 minutes. Without pressing the brake pedal, press the start button once or turn the key halfway to the ON position (without depressing the clutch). The vehicle will perform a self-diagnostic check upon power-up. After 5-10 seconds, check if the warning light turns off. If the light remains on, visit a service center promptly. Technicians can use diagnostic tools to read trouble codes, identify specific issues, and perform targeted repairs.
