What Causes the Engine Malfunction Light to Illuminate in a Mercedes-Benz?

[Gemma]

The main reasons for the engine malfunction light to illuminate include issues with sensors, car maintenance problems, fuel quality issues, poor combustion of the air-fuel mixture, engine intake problems, turbocharging issues, exhaust system problems, and faults in the anti-theft system. Additionally, when starting the car, the vehicle performs a self-check on the engine system. Under normal circumstances, the engine malfunction light will turn off after the self-check is completed. If it remains on for an extended period, it is advisable to seek professional help at a service station promptly to diagnose and eliminate potential safety hazards. Detailed explanations for each type of fault are as follows: Sensor Issues: Sensors include those for coolant temperature, crankshaft position, air flow, intake air temperature, oxygen sensors, etc. When these sensors are damaged, have poor contact, or experience signal interruption, the car's ECU cannot accurately obtain engine data, leading to the illumination of the engine malfunction light. In such cases, it is essential to visit a service center for professional diagnosis and timely elimination of safety hazards. Maintenance Issues: Poor engine maintenance is the most common cause of the engine malfunction light illuminating. Vehicles have specific maintenance schedules, and failure to adhere to these schedules, combined with poor driving habits, can increase the engine's operational burden, eventually causing the engine malfunction light to alert the owner of a fault. Fuel Quality Issues: This refers to both fuel and engine oil. The fuel used in cars typically has a specific octane rating, and engine oil can be semi-synthetic or fully synthetic. Manufacturers usually recommend the type of fuel and engine oil to use. If the owner fails to follow these recommendations, prolonged use can lead to engine wear, triggering the malfunction light. It is crucial to use the recommended fuel octane rating and appropriate engine oil. Poor Combustion of Air-Fuel Mixture: Faults in spark plugs, ignition coils, fuel pumps, or clogged fuel lines can cause poor combustion of the air-fuel mixture in the engine. This leads to engine carbon buildup or knocking, which the oxygen sensor detects and reports to the ECU, resulting in the illumination of the malfunction light as a warning. Intake Issues: The engine requires air for combustion, and the air filter plays a critical role in this process. If the air filter is dirty or not cleaned regularly, it can affect the engine's air intake, potentially leading to blockages over time. Severe cases can cause the engine malfunction light to illuminate. Turbocharging Issues: Problems with the intake turbocharging pipes or the turbocharger itself 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. Exhaust System Issues: Faults in the rear oxygen sensor, catalytic converter, exhaust camshaft, or bearings can cause the engine malfunction light to illuminate. The most common issue is a faulty catalytic converter, which can result from using leaded gasoline, lead or silicon-based lubricant additives, physical damage to the catalytic converter, or faults in the engine's fuel supply system. Anti-Theft System: If the car's electronic anti-theft system malfunctions or the anti-theft controller does not match the engine's electronic controller, the anti-theft system can prevent the engine from operating normally, accompanied by the illumination of the engine malfunction light. Solutions for the Engine Malfunction Light: If the engine malfunction light is on and the car cannot start, this may be due to a faulty fuel pump or ignition components. It is recommended to call for assistance immediately. If the engine malfunction light is on, the car can still be driven, but experiences severe shaking or loss of power, it is advisable to pull over safely and call for roadside assistance. If the engine malfunction light is on but the car drives normally, this may indicate a faulty sensor. In such cases, the car can be driven cautiously at low to medium speeds, but it is best to visit a repair shop soon to eliminate potential safety hazards.