The engine malfunction light may illuminate due to the following 7 primary reasons: Sensor failure: This includes sensors such as coolant temperature, crankshaft position, air flow, intake temperature, and oxygen sensors. When these sensors are damaged, have poor connections, or experience signal interruptions, the vehicle's ECU cannot accurately obtain engine data, triggering the malfunction light. Fuel/oil quality issues: Failure to use the manufacturer-recommended fuel or engine oil may cause engine wear, leading to the malfunction light activation. Poor fuel mixture combustion: Incomplete combustion can cause engine carbon buildup or knocking. When detected by oxygen sensors and reported to the ECU, the malfunction light will illuminate as a warning. Contributing factors include spark plug failure, ignition coil issues, fuel pump malfunction, or fuel line blockage. Turbocharger problems: Issues with the intake boost system or turbocharger can trigger the light. Common turbocharger failures may be accompanied by oil leaks, excessive oil consumption, power loss, metallic noises, or blue/black exhaust smoke. Air intake issues: Obstructed engine air intake passages, often caused by dirty air filters that haven't been regularly cleaned, may eventually activate the malfunction light. Exhaust system faults: Problems like rear oxygen sensor failure, catalytic converter issues (most common), or exhaust camshaft/bearing failures can trigger the light. Leaded gasoline, improper lubricant additives, physical damage to the catalytic converter, or fuel system malfunctions often cause catalytic converter problems. Anti-theft system malfunction: If the electronic anti-theft system fails or isn't properly synchronized with the engine control unit, it may prevent normal engine operation while activating the warning light. When the engine light illuminates, follow these steps: 1. First check if the engine operates normally. If there's shaking, black smoke, or other abnormalities (especially with a red warning light), do not restart the engine. 2. If restarting is possible, wait 5-10 minutes after turning off the engine. Without pressing the brake pedal, 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 for 5-10 seconds - observe if the warning light turns off. 3. If the light remains on, visit a service center immediately. Technicians can use diagnostic tools to read trouble codes and perform targeted repairs.
