What Are the Causes of the Engine Malfunction Light?

[VanColin]

The engine malfunction light may illuminate for the following 7 main reasons: 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 their signals are interrupted, the vehicle's ECU cannot accurately obtain engine data, which may trigger the engine malfunction light. Fuel or oil quality issues: If the fuel or engine oil is not added as required by the manufacturer, it may cause engine wear and trigger 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 faulty spark plugs, ignition coils, fuel pumps, or clogged fuel lines can cause poor combustion of the air-fuel mixture. Turbocharging problems: Issues with the intake boost piping or turbocharger can also cause the engine malfunction light to illuminate. The most common issue is a damaged turbocharger, accompanied by symptoms like oil leaks, excessive oil consumption, reduced power, metallic noises, or blue/black smoke from the exhaust. Intake problems: If the vehicle's intake system has issues, it may lead to blocked engine pipes, and in severe cases, trigger the engine malfunction light. A dirty air filter that is not cleaned regularly can cause intake problems. Exhaust problems: Exhaust system failures can also cause the engine malfunction light to illuminate. Common causes include faults in the rear oxygen sensor, catalytic converter, exhaust camshaft, or bearings, with the catalytic converter being the most frequent issue. Using leaded gasoline, lead- or silicon-containing lubricant additives, physical damage to the catalytic converter, or fuel system malfunctions can easily lead to catalytic converter failure. 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 trigger the engine malfunction light. If the engine malfunction light is on, follow these steps: First, check whether the engine is running normally, and if there are issues like shaking or black smoke, avoid restarting the engine. Particularly, do not restart the engine if the red warning light is on. If the engine can start, 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 to see if the malfunction light on the dashboard turns off. If the light remains on, visit a service center as soon as possible. The service center can use a portable diagnostic tool to read the fault codes, identify the issue, and perform targeted repairs.