What are the reasons for the engine warning light to come on?

[McMaya]

There are mainly 7 reasons for the engine warning light to come on: Sensor malfunction: The sensors mentioned here include coolant temperature, crankshaft position, air flow, intake air temperature, oxygen sensors, etc. When these sensors are damaged, have poor contact, or signal interruption occurs, 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 according to the manufacturer's requirements, it may cause engine wear and trigger the warning light. Poor combustion of air-fuel mixture: Poor combustion can lead to engine carbon deposits or knocking. When detected by the oxygen sensor and reported to the ECU, the warning light will illuminate as a warning. Spark plug failure, ignition coil failure, fuel pump failure, and fuel line blockage can all cause poor combustion of the air-fuel mixture. Turbocharging issues: The intake boost pipe or 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 noise, and blue or black smoke from the exhaust pipe. Intake issues: If there is a problem with the car's intake system, it may cause engine pipe 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 system faults can also cause the engine warning light to come on. The rear oxygen sensor, catalytic converter, exhaust camshaft, and bearing failure are all causes of exhaust problems, with the catalytic converter being the most common. Using leaded gasoline, lead or silicon-based lubricant additives, physical damage to the catalytic converter, or fuel system faults can easily cause catalytic converter failure. Anti-theft system malfunction: 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 prevent the engine from operating normally, and the engine warning light will come on. If the engine warning light comes on, you can follow these steps: First, check if the engine is running normally and whether there are issues like shaking or black smoke. 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 for 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 after powering on. Wait for 5-10 seconds and observe if the warning light on the dashboard turns off. If the warning light remains on, visit a service station as soon as possible. The service station can use a portable diagnostic tool to read the fault code, obtain fault information, and perform targeted repairs.

[MaverickMarie]

I've been driving for almost twenty years, and it's really nerve-wracking when the engine warning light comes on. I remember last time my car's light suddenly lit up, and it felt shaky and weak when driving. I rushed to the repair shop for a check, and it turned out the oxygen sensor was faulty, causing abnormal emission data. The mechanic also checked the spark plugs and found they were worn out—unstable ignition systems can easily trigger the warning light. Other common causes include clogged fuel injectors or air intake leaks, which affect the air-fuel mixture combustion. If it's a fuel quality issue or low battery voltage, the light might also come on falsely. In short, timely repairs are crucial—don't delay, or small issues can turn into major repairs. Regular oil and filter changes can help prevent such troubles.