The engine malfunction light comes in two colors: yellow and red. When the yellow malfunction light is on, you can continue driving. When the red malfunction light is on, you must stop driving immediately. When the yellow malfunction light is on, it serves as a warning, indicating that certain system parameters in the car may have exceeded the set range. The car can still be driven, but some functions may be limited. When the red malfunction light is on, it means the issue is severe, and the car must be stopped immediately. Turn off the engine, refrain from driving further, and check for the source of the malfunction. There are seven main reasons why the engine malfunction light may come on: 1. Sensor malfunction: This includes sensors such as the coolant temperature sensor, crankshaft position sensor, air flow sensor, intake air temperature sensor, and oxygen sensor. If these sensors are damaged, have poor connections, or their signals are interrupted, the car's ECU cannot accurately obtain engine data, triggering the malfunction light. 2. Fuel or oil quality issues: If you do not use the fuel or oil specified by the manufacturer, it may cause engine wear and trigger the malfunction light. 3. Poor fuel mixture combustion: 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. Spark plug failure, ignition coil failure, fuel pump failure, or clogged fuel lines can all cause poor fuel mixture combustion. 4. Turbocharger issues: Problems with the intake boost piping or turbocharger can also trigger the engine malfunction light. The most common issue is turbocharger damage, accompanied by symptoms such as oil leaks, excessive oil consumption, reduced power, metallic noises, or blue/black smoke from the exhaust. 5. Intake problems: If the car's intake system is compromised, it may lead to clogged engine passages, which can trigger the malfunction light in severe cases. A dirty or uncleaned air filter can cause intake issues. 6. Exhaust problems: Exhaust system failures can also trigger the malfunction light. Common causes include rear oxygen sensor failure, catalytic converter issues, or faults in the exhaust camshaft and bearings. The catalytic converter is the most frequent culprit. Using leaded gasoline, lead- or silicon-based lubricant additives, physical damage to the catalytic converter, or fuel system malfunctions can all lead to catalytic converter failure. 7. Anti-theft system malfunction: If the car'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, triggering the malfunction light. If the engine malfunction light comes on, follow these steps: 1. First, check whether the engine is running normally. Look for signs such as shaking or black smoke. If these symptoms are present, avoid restarting the engine. Note: If the red light is on, do not restart the engine under any circumstances. 2. 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 car will enter self-check mode. Wait 5-10 seconds to see if the malfunction light turns off. 3. If the light remains on, visit a service center as soon as possible. Technicians can use a portable diagnostic tool to read the error codes, identify the issue, and perform targeted repairs.
