The engine fault light may illuminate due to the following 7 main reasons: Sensor malfunction: Sensors such as coolant temperature, crankshaft position, air flow, intake temperature, and oxygen sensors may be damaged, have poor contact, or experience signal interruption. When the car's ECU cannot accurately obtain engine data, the engine fault light will illuminate. 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 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 illuminate as a warning. Spark plug failure, ignition coil failure, fuel pump failure, or fuel line blockage can all cause poor combustion of the air-fuel mixture. Turbocharging issues: The intake turbocharging pipeline or turbocharger can also cause the engine fault light to illuminate. The most common issue is turbocharger damage, accompanied by symptoms such as oil leakage, high oil consumption, reduced power, metallic noises, or blue/black smoke from the exhaust pipe. Intake issues: If there is a problem with the car's intake, it may lead to engine pipeline blockage, and in severe cases, the engine fault light will illuminate. A dirty air filter that is not cleaned regularly can cause intake problems. Exhaust issues: Exhaust faults can also trigger the engine fault light. Common causes include rear oxygen sensor failure, three-way catalytic converter failure, exhaust camshaft and bearing failure, with the three-way catalytic converter being the most frequent issue. Using leaded gasoline, lead or silicon-containing lubricant additives, physical damage to the catalytic converter, or fuel supply system failures can easily cause three-way catalytic converter problems. Anti-theft system malfunction: If the car's electronic anti-theft system fails 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 fault light will illuminate. If the engine fault light is on, follow these steps: First, check if the engine is running normally and if there are issues such as 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 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 enter self-check 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 station as soon as possible. The service station can use a portable diagnostic tool to read the fault code, identify the issue, and perform targeted repairs.
