There are primarily 7 reasons for the engine malfunction light to illuminate: Sensor failure: The sensors mentioned here include those for coolant temperature, crankshaft position, air flow, intake air temperature, oxygen, etc. When these sensors are damaged, have poor contact, or experience signal interruption, the vehicle's ECU cannot accurately obtain engine data, which triggers the engine malfunction light. Fuel and oil quality issues: If fuel and engine oil are not added according to the manufacturer's requirements, it may cause engine wear, leading to the illumination of the malfunction light. Poor combustion of the air-fuel mixture: Poor combustion can lead to engine carbon buildup 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 engine's air-fuel mixture. Turbocharging problems: The intake turbocharging pipeline and turbocharger can also cause the engine malfunction light to illuminate. The most common issue is turbocharger damage, accompanied by symptoms such as oil leaks, high oil consumption, reduced power, metallic noises, or blue/black smoke from the exhaust pipe. Intake problems: If there are issues with the vehicle's intake, it may lead to engine pipeline blockages, and in severe cases, cause the engine malfunction light to illuminate. A dirty air filter that is not regularly cleaned can lead to intake problems. Exhaust problems: Exhaust faults can also trigger the engine malfunction light. Common causes include rear oxygen sensor failure, three-way catalytic converter issues, exhaust camshaft and bearing faults, with the three-way catalytic converter being the most frequent. Using leaded gasoline, lead or silicon-containing lubricant additives, physical damage to the catalytic converter, or fuel supply system failures can easily lead to three-way catalytic converter problems. Anti-theft system failure: If the vehicle's electronic anti-theft system malfunctions or if there is a mismatch between the anti-theft controller and the engine electronic controller, the anti-theft system can prevent the engine from operating normally, and the engine malfunction light will illuminate. If the engine malfunction light is on, follow these steps: First, check if the engine is operating normally, looking for signs such as shaking or black smoke. If these symptoms are present, 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 and wait for 5-10 minutes. 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 to see if the malfunction light turns off on the dashboard. If the malfunction light remains on, visit a service station as soon as possible for diagnosis. The service station can use a portable diagnostic tool to read the fault codes, identify the issue, and perform targeted repairs.
