Can Poor Quality Fuel Cause the Engine Malfunction Light to Illuminate?

[MacGarrett]

If the engine malfunction light comes on after refueling, it indicates that low-quality fuel has been added. During the combustion process in the engine, poor-quality fuel with excessive impurities and low combustion efficiency leaves behind residues and unburned fuel. These accumulate in the combustion chamber, occupying space and triggering the engine malfunction light. Solution: Promptly drain the low-quality fuel and clean the fuel tank and fuel lines. After cleaning, replace with high-quality fuel. Besides fuel quality issues, the engine malfunction light may illuminate due to the following reasons: Sensor Malfunction: Sensors such as coolant temperature, crankshaft position, air flow, intake temperature, and oxygen sensors, when damaged, poorly connected, or interrupted, prevent the vehicle's ECU from accurately obtaining engine data, leading to the illumination of the engine malfunction light. Poor Combustion of Air-Fuel Mixture: Poor combustion can cause engine carbon buildup or knocking. When detected by the oxygen sensor and reported to the ECU, the malfunction light will illuminate as a warning. Issues like faulty spark plugs, ignition coils, fuel pump, or clogged fuel lines can lead to poor combustion. Turbocharger Issues: Problems with the intake boost piping or turbocharger can also trigger the engine malfunction light. The most common issue is turbocharger damage, accompanied by symptoms like oil leaks, excessive oil consumption, reduced power, metallic noises, or blue/black smoke from the exhaust. Intake Issues: Blockages in the engine intake system can cause the engine malfunction light to illuminate, especially if the air filter is dirty and not regularly cleaned. Exhaust Issues: Exhaust system faults, such as issues with the rear oxygen sensor, catalytic converter, exhaust camshaft, or bearings, can trigger the light. The catalytic converter is particularly prone to failure due to leaded gasoline, lead/silicon-based lubricant additives, physical damage, or fuel system malfunctions. Anti-Theft System Fault: If the car's electronic anti-theft system malfunctions or the anti-theft controller is incompatible with the engine ECU, it can prevent the engine from operating normally and trigger the malfunction light.