What Causes the Sudden Illumination of the Engine Malfunction Light?

[DeBriella]

The engine malfunction light may illuminate due to the following 7 main 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 contact, or experience signal interruption, the vehicle's ECU cannot accurately obtain engine data, triggering the malfunction light. Fuel Quality Issues: Failure to use the fuel and engine oil specified by the manufacturer may lead to engine wear, causing the malfunction light to illuminate. Poor Combustion of Air-Fuel Mixture: Poor combustion can result in 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 cause poor combustion. Turbocharging Problems: The intake boost pipeline or turbocharger can also trigger the engine malfunction light. The most common issue is turbocharger damage, 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 malfunctions, it may cause engine pipeline blockages, potentially leading to the illumination of the malfunction light. A dirty or uncleaned air filter can also cause intake issues. Exhaust Problems: Exhaust system failures can also trigger the malfunction light. Causes include rear oxygen sensor failure, catalytic converter issues, exhaust camshaft or bearing failure, with the catalytic converter being the most common culprit. Using leaded gasoline, lead- or silicon-based lubricant additives, physical damage to the catalytic converter, or fuel system failures can easily cause catalytic converter problems. Anti-Theft System Malfunction: If the vehicle's electronic anti-theft system fails or the anti-theft controller does not match the engine ECU, the anti-theft system may prevent the engine from operating normally, accompanied by the illumination of the malfunction light. If the engine malfunction light illuminates, follow these steps: First, check if the engine is running normally, such as whether there is shaking, black smoke, etc. If so, avoid restarting the engine. Note: Do not restart the engine if the red warning light is on. If the engine can start, turn it off and wait 5-10 minutes. Without pressing the brake, press the start button once or turn the key halfway to the 'ON' position (without pressing the clutch). The vehicle will perform a self-check after powering on. Wait 5-10 seconds to see if the malfunction light turns off. If the light remains on, visit a service center as soon as possible. Technicians can use a portable diagnostic tool to read the trouble codes, identify the issue, and perform targeted repairs.