What does it mean when the car's engine warning light is yellow?

[EmmettAnn]

The yellow engine warning light indicates a warning, meaning that certain system parameters of the car may be out of the set range. At this time, the car can continue to drive, but some functions may be limited. The engine warning light can also be red. A red warning light means prohibition, indicating that the car must stop immediately, turn off the engine, and prohibit further driving. The fault must be checked. There are mainly 7 reasons why the engine warning light comes on: Sensor failure: The sensors mentioned here include coolant temperature, crankshaft position, air flow, intake temperature, oxygen sensors, etc. When these sensors are damaged, have poor contact, or signal interruption, the car's ECU cannot accurately obtain engine data, which will cause the engine warning light to come on. Fuel quality issues: If fuel and engine oil are not added as required by the manufacturer, it may cause engine wear and trigger the warning light. Poor mixture combustion: Poor mixture combustion can lead to engine carbon deposits or knocking. After being detected by the oxygen sensor and reported to the ECU, the warning light will come on as a warning. Spark plug failure, ignition coil failure, fuel pump failure, and fuel line blockage can all cause poor mixture combustion in the engine. Turbocharging issues: The intake turbocharging pipeline and turbocharger can also cause the engine warning light to come on. The most common issue is turbocharger damage, accompanied by symptoms such as oil leakage, high oil consumption, reduced power, metal noises, and blue or black smoke from the exhaust pipe. Intake issues: If there is a problem with the car's intake, it may cause engine pipeline blockage, and in severe cases, trigger the engine warning light. A dirty air filter that is not cleaned regularly can lead to intake problems. Exhaust issues: Exhaust faults can also cause the engine warning light to come on. The rear oxygen sensor, three-way catalytic converter, exhaust camshaft, and bearing failures are all causes of exhaust problems, with the three-way catalytic converter being the most common. Using leaded gasoline, lead or silicon-containing lubricant additives, physical damage to the three-way catalytic converter, or engine fuel supply system failures can easily cause three-way catalytic converter issues. Anti-theft system failure: If the car's electronic anti-theft system malfunctions or the anti-theft controller does not match the engine electronic controller, the anti-theft system can also prevent the engine from working properly and trigger the engine warning light. If the engine warning light comes on, follow these steps: First, check whether the engine is running normally and if there are any issues such as shaking or smoke. If so, try not to restart the engine. Especially, do not restart if the red 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 pressing the clutch. The car will perform a self-check after powering on. Wait for 5-10 seconds and observe whether the warning light on the dashboard turns off. If the warning light does not turn off, visit a service station as soon as possible to identify the cause. The service station can use a portable diagnostic tool to read the fault code, obtain fault information, and perform targeted repairs.