There are primarily 7 reasons for the engine malfunction indicator light to turn on: 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 cause the engine malfunction indicator light to turn on. 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 malfunction light. Poor combustion of the air-fuel mixture: Poor combustion of the air-fuel mixture can lead to engine carbon deposits or knocking. When detected by the oxygen sensor and reported to the ECU, the malfunction light will illuminate as a warning. Issues such as 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: The intake turbocharging pipeline and turbocharger can also cause the engine malfunction light to turn on. The most common issue is turbocharger damage, accompanied by symptoms such as oil leakage, high oil consumption, reduced power, metallic noises, or blue/black smoke from the exhaust pipe. Intake issues: If there are problems with the vehicle's intake system, it may cause engine pipeline blockages, and in severe cases, trigger the engine malfunction light. A dirty air filter that is not cleaned regularly can lead to intake problems. Exhaust issues: Exhaust system faults can also cause the engine malfunction light to turn on. Common causes include rear oxygen sensor failure, catalytic converter issues, exhaust camshaft and bearing failure, with the catalytic converter being the most frequent culprit. Using leaded gasoline, lead or silicon-based lubricant additives, physical damage to the catalytic converter, or fuel system failures can easily lead to catalytic converter problems. Anti-theft system failure: If the vehicle's electronic anti-theft system malfunctions or if the anti-theft controller does not match the engine electronic controller, the anti-theft system can prevent the engine from operating normally, and the engine malfunction light will turn on. If the engine malfunction light turns on, follow these steps: First, check if the engine is running normally and if there are issues such as shaking or black smoke. If so, avoid restarting the engine. Particularly, do not restart the engine if the red warning light is on. If the engine can be started, turn it off for 5-10 minutes. Then, without pressing the brake, press the start button once or turn the key halfway to the 'on' position without depressing the clutch. The vehicle will perform a self-check after powering on. Wait for 5-10 seconds and observe if the malfunction light on the dashboard turns off. If the malfunction light remains on, visit a service station as soon as possible to diagnose the issue. The service station can use a portable diagnostic tool to read the fault codes, identify the problem, and perform targeted repairs.
