What Does It Mean When the Engine Malfunction Light Comes On?

[SanCaroline]

The engine malfunction light may illuminate due to the following 7 main reasons: Sensor malfunction: This includes sensors such as coolant temperature, crankshaft position, air flow, intake air 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 malfunction light. Fuel/oil quality issues: Failure to use the fuel and engine oil as specified by the manufacturer may cause engine wear, leading to the malfunction light activation. Poor combustion of air-fuel mixture: Incomplete 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. Spark plug failure, ignition coil issues, fuel pump malfunction, or fuel line blockage can all result in poor combustion. Turbocharging problems: Issues with the intake boost piping or turbocharger may trigger the engine light. The most common is turbocharger damage, often accompanied by oil leaks, excessive oil consumption, reduced power, metallic noises, or blue/black smoke from the exhaust. Intake problems: Air intake issues may cause engine piping blockage, potentially triggering the malfunction light. A dirty air filter that hasn't been regularly cleaned can lead to intake problems. Exhaust system faults: Exhaust issues can also activate the engine light. Common causes include rear oxygen sensor failure, three-way catalytic converter problems, or exhaust camshaft and bearing wear. The three-way catalyst is most frequently affected, often due to using leaded gasoline, lead/silicon-containing lubricant additives, physical damage to the catalyst, or fuel system malfunctions. Anti-theft system failure: If the electronic anti-theft system malfunctions or the immobilizer doesn't match with the engine ECU, the system may prevent normal engine operation while illuminating the malfunction light. When the engine light comes on, follow these steps: First check if the engine operates normally. If there's shaking, black smoke, etc., avoid restarting. Note: Never restart if the red warning light is on. If the engine can start, turn off for 5-10 minutes, then without pressing brakes, push the start button (or turn the key halfway to ON position without depressing clutch). The vehicle will perform self-diagnosis for 5-10 seconds - observe if the warning light turns off. If the light persists, visit a service center immediately. Technicians can read trouble codes using diagnostic tools to identify and fix specific issues.