The engine malfunction indicator light being on may serve as a warning, indicating that certain system parameters in the vehicle may have exceeded the set range. In such cases, the vehicle can usually continue to drive, and the light is typically yellow. There is also a more severe situation where the light turns red, indicating a very serious malfunction. Although the vehicle might still be operable, for safety reasons, it is imperative to stop immediately, turn off the engine, refrain from further driving, and check for the source of the malfunction. There are primarily seven reasons why the engine malfunction indicator light may come on: Sensor malfunction: The sensors referred to here include those for coolant temperature, crankshaft position, air flow, intake air temperature, oxygen, etc. When these sensors are damaged, have poor contact, or their signals are interrupted, the vehicle's ECU cannot accurately obtain engine data, leading to the illumination of the engine malfunction light. Fuel quality issues: Failure to add fuel and engine oil as required by the manufacturer may cause engine wear, resulting in the malfunction light turning on. Poor combustion of the air-fuel mixture: Poor combustion can lead to engine carbon buildup or knocking. Once 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 issues: The intake turbocharging pipeline and turbocharger can also cause the engine malfunction light to come on. The most common issue is turbocharger damage, accompanied by symptoms like oil leaks, high oil consumption, reduced power, metallic noises, or blue/black smoke from the exhaust. Intake issues: Problems with the car's intake system can lead to engine pipeline blockages, and in severe cases, trigger the engine malfunction light. A dirty air filter that hasn't been cleaned regularly can cause intake problems. Exhaust issues: Exhaust system malfunctions can also cause the engine malfunction light to illuminate. Causes include faults in the rear oxygen sensor, three-way catalytic converter, exhaust camshaft, and bearing wear, with the three-way catalytic converter being the most common culprit. Using leaded gasoline, lead or silicon-containing lubricant additives, physical damage to the catalytic converter, or faults in the engine's fuel supply system can easily lead to three-way catalytic converter failure. Anti-theft system malfunction: 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 come on. If the engine malfunction light is on, you can follow these steps: First, check if the engine is running normally, looking for signs of shaking, smoke, etc. If such symptoms are present, avoid restarting the engine. Particularly, if the light is red, do not restart the engine under any circumstances. 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 upon powering up. After 5-10 seconds, observe whether the malfunction light on the dashboard turns off. If the light remains on, proceed to 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.
