The engine fault light may illuminate due to the following 7 main reasons: Sensor malfunction: This includes sensors such as coolant temperature, crankshaft position, air flow, intake temperature, and oxygen sensors. When these sensors are damaged, have poor contact, or experience signal interruption, the vehicle's ECU cannot accurately obtain engine data, triggering the engine fault light. Fuel/oil quality issues: Failure to use the manufacturer-recommended fuel or engine oil may cause engine wear, leading to the fault light activation. Poor fuel mixture combustion: This can result in engine carbon buildup or knocking. When detected by the oxygen sensor and reported to the ECU, the fault light will illuminate as a warning. Causes include spark plug failure, ignition coil malfunction, fuel pump issues, or fuel line blockage. Turbocharging problems: Issues with the intake boost pipes or turbocharger can trigger the engine fault light. The most common is turbocharger damage, often accompanied by oil leaks, excessive oil consumption, power loss, metallic noises, or blue/black exhaust smoke. Intake system issues: Air intake problems may cause engine pipe blockages, potentially triggering the fault light. A dirty air filter that hasn't been regularly cleaned can lead to intake problems. Exhaust system problems: Exhaust faults can also cause the engine light to illuminate. Common causes include rear oxygen sensor failure, catalytic converter issues, or exhaust camshaft and bearing wear. Using leaded gasoline, certain oil additives, physical damage to the catalytic converter, or fuel system malfunctions may damage the catalytic converter. Anti-theft system malfunction: If the vehicle's electronic anti-theft system fails or the anti-theft controller doesn't match the engine ECU, the system may prevent normal engine operation while illuminating the fault light. When the engine fault light appears, follow these steps: First check if the engine operates normally. If there's shaking, black smoke, or other abnormalities, avoid restarting the engine. Note: Never restart if the light is red. If the engine can start, turn it off for 5-10 minutes. Without pressing the brake, push the start button once or turn the key halfway to the ON position (without engaging the clutch). The vehicle will perform a self-check for 5-10 seconds - observe if the warning light turns off. If the light remains on, visit a service center promptly. Technicians can use diagnostic tools to read trouble codes, identify the issue, and perform targeted repairs.
