What Causes the Engine Malfunction Light to Come On After Refueling?

[DelNolan]

If fuel and engine oil are not added according to the manufacturer's requirements, it may cause engine wear and trigger the malfunction light. In this case, the fuel in the tank should be drained, and the tank should be thoroughly cleaned. After cleaning, add gasoline that meets the required standards. Apart from fuel quality issues, here are six common factors that can cause the engine malfunction light to illuminate: Sensor failure: This includes sensors such as coolant temperature, crankshaft position, air flow, intake temperature, and oxygen sensors. When these sensors are damaged, have poor connections, or experience signal interruptions, the vehicle's ECU cannot accurately obtain engine data, leading to the illumination of the engine malfunction light. Poor combustion of the 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 such as faulty spark plugs, ignition coils, fuel pumps, or clogged fuel lines can lead to poor combustion of the air-fuel mixture. Turbocharging issues: Problems with the intake boost piping or turbocharger can also trigger the engine malfunction light. The most common issue is a damaged turbocharger, accompanied by symptoms such as oil leaks, excessive oil consumption, reduced power, metallic noises, or blue/black smoke from the exhaust. Intake problems: If the vehicle's intake system malfunctions, it may lead to clogged engine pipes, and in severe cases, the engine malfunction light will illuminate. A dirty air filter that is not cleaned regularly can cause intake issues. Exhaust problems: Exhaust system failures can also trigger the engine malfunction light. Causes include faulty rear oxygen sensors, catalytic converters, exhaust camshafts, or bearings. The most common issue is a malfunctioning catalytic converter, often caused by using leaded gasoline, lead- or silicon-based lubricant additives, physical damage to the catalytic converter, or fuel system failures. Anti-theft system malfunction: If the vehicle's electronic anti-theft system fails or if the anti-theft controller does not match the engine control unit, the anti-theft system can prevent the engine from operating normally, and the engine malfunction light will illuminate.