What are the reasons for the engine malfunction indicator light staying on during normal driving?

[DeMadeline]

There are mainly 7 reasons for the engine malfunction indicator light to illuminate: Sensor malfunction: 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 signal interruption, the vehicle's ECU cannot accurately obtain engine data, which will then cause the engine malfunction indicator light to illuminate. Fuel quality issues: If fuel and engine oil are not added according to the manufacturer's requirements, it may cause engine wear, leading to the malfunction indicator light illuminating. Poor mixture combustion: Poor mixture combustion can cause engine carbon deposits or knocking. After being detected by the oxygen sensor and reported to the ECU, the malfunction indicator light will illuminate as a warning. Spark plug failure, ignition coil failure, fuel pump failure, fuel line blockage, etc., can all cause poor engine mixture combustion. Turbocharging issues: The intake turbocharging pipeline and turbocharger can also cause the engine malfunction indicator light to illuminate. The most common issue is turbocharger damage, accompanied by symptoms such as oil leakage, high oil consumption, reduced power, metal noises, blue or black smoke from the exhaust pipe. Intake issues: If there is a problem with the car's intake, it may cause engine pipeline blockage, and in severe cases, the engine malfunction indicator light will illuminate. If the air filter is not clean and not regularly cleaned, it can lead to intake problems. Exhaust issues: Exhaust faults can also cause the engine malfunction indicator light to illuminate. The rear oxygen sensor, three-way catalytic converter, exhaust camshaft, and bearing failures are all causes of exhaust problems, with the three-way catalytic converter being the most common. Using leaded gasoline, lead or silicon-containing lubricant additives, impact damage to the three-way catalytic converter, and engine fuel supply system failures can easily cause three-way catalytic converter faults. Anti-theft system malfunction: If the car's electronic anti-theft system malfunctions, or if the anti-theft controller does not match the engine electronic controller, the anti-theft system can also cause the engine to not work properly, and the engine malfunction indicator light will illuminate. If the engine malfunction indicator light is on, you can follow these steps to handle it: First, check whether the engine is operating normally, whether there is shaking, black smoke, etc. If there is, try not to start it again. Especially note, do not start the engine if the red light is on. If the engine can start, after turning it off for 5-10 minutes, do not press the brake, directly press the start button, or without pressing the clutch, turn the car key halfway to the 'on' position. The car will perform a self-check function after powering on. Wait for 5-10 seconds and observe whether the malfunction indicator light on the dashboard goes off. If the malfunction indicator light does not go off, please go to a service station as soon as possible to find out the reason. The service station can read the fault code through a portable diagnostic tool to obtain fault information and perform targeted repairs.