What does it mean when the engine fault warning light comes on?

[OliveLynn]

There are mainly 7 reasons why the engine fault light comes on: Sensor failure: The sensors mentioned here include those for coolant temperature, crankshaft position, air flow, intake air temperature, oxygen, etc. When these sensors are damaged, have poor contact, or their signals are interrupted, the car's ECU cannot accurately obtain engine data, which will cause the engine fault 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 fault light. Poor combustion of the 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 fault light will come on as a warning. Issues like spark plug failure, ignition coil failure, fuel pump failure, or fuel line blockage can all cause poor combustion of the air-fuel mixture. Turbocharging problems: The intake turbocharging pipeline and turbocharger can also cause the engine fault light to come on. The most common issue is turbocharger damage, accompanied by symptoms like oil leaks, high oil consumption, reduced power, metallic noises, or blue/black smoke from the exhaust. Intake problems: If there are issues with the car's intake, it may lead to engine pipeline blockage, and in severe cases, the engine fault light will come on. A dirty air filter that hasn't been cleaned regularly can cause intake problems. Exhaust problems: Exhaust faults can also trigger the engine fault light. Common causes include issues with the rear oxygen sensor, catalytic converter, exhaust camshaft, and bearings, with the catalytic converter being the most frequent problem. Using leaded gasoline, lead or silicon-based lubricant additives, physical damage to the catalytic converter, or fuel system failures can easily cause catalytic converter issues. Anti-theft system failure: If the car's electronic anti-theft system malfunctions or the anti-theft controller doesn't match the engine electronic controller, the anti-theft system can prevent the engine from working properly, and the engine fault light will come on. If the engine fault light comes on, follow these steps: First, check if the engine is running normally, such as whether there is 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 be started, turn it off and wait for 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-test mode after powering on. Wait for 5-10 seconds to see if the fault light turns off. If the fault light remains on, visit a service center as soon as possible. The service center can use a portable diagnostic tool to read the fault codes, identify the issue, and perform targeted repairs.