The engine warning light comes in two colors: yellow and red. When the yellow warning light is on, you can continue driving. When the red warning light is on, you must stop driving immediately. When the yellow warning 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 at this time, but some functions may be limited. When the red warning light is on, it means the issue is severe. The car must be stopped immediately, the engine turned off, and driving must cease. The fault must then be checked and addressed. There are seven main reasons why the engine warning light may come on: Sensor failure: 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 contact, or their signals are interrupted, the car's ECU cannot accurately obtain engine data, triggering the engine warning light. Fuel or oil quality issues: If the fuel or engine oil is not added as specified by the manufacturer, it may cause engine wear, leading to the warning light turning on. Poor combustion of the air-fuel mixture: Poor combustion can cause engine carbon buildup or knocking. When detected by the oxygen sensor and reported to the ECU, the warning light will illuminate. Issues such as faulty spark plugs, ignition coils, fuel pump failure, or clogged fuel lines can cause poor combustion. Turbocharger problems: Issues with the intake boost pipes or turbocharger can also trigger the engine warning light. 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 car's intake system is compromised, it may lead to clogged engine pipes, potentially triggering the warning light. A dirty or uncleaned air filter can cause intake issues. Exhaust problems: Exhaust system faults can also cause the engine warning light to come on. Common causes include faulty rear oxygen sensors, catalytic converter issues, or problems with the exhaust camshaft and bearings. The catalytic converter is most frequently affected, often due to the use of leaded gasoline, lead or silicon-based oil additives, physical damage, or fuel system faults. Anti-theft system failure: If the car's electronic anti-theft system malfunctions or the anti-theft controller is incompatible with the engine ECU, the engine may not operate correctly, and the warning light will illuminate. If the engine warning light comes on, follow these steps: First, check if the engine is running normally. Look for signs like shaking or black smoke. If present, avoid restarting the engine. Note: If the red light is on, do not restart the engine under any circumstances. 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 depressing the clutch. The car will enter self-check mode. Wait 5-10 seconds to see if the warning light turns off. If the light remains on, visit a service center as soon as possible. Technicians can use a diagnostic tool to read the fault code, identify the issue, and perform targeted repairs.
