What does it mean when the engine malfunction indicator light comes on?
2 Answers
There are 7 common reasons for the engine malfunction light to illuminate: Sensor malfunction: The sensors mentioned here include 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 vehicle's ECU cannot accurately obtain engine data, which will trigger the engine malfunction light. Fuel quality issues: If fuel and engine oil are not added according to the manufacturer's requirements, it may cause engine wear and trigger the malfunction light. Poor mixture combustion: Poor mixture combustion can lead to 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 failure, fuel pump failure, and fuel line blockage can all cause poor mixture combustion in the engine. Turbocharging issues: The intake boost pipeline and turbocharger can also cause the engine malfunction light to illuminate. The most common issue is turbocharger damage, accompanied by symptoms such as oil leaks, excessive oil consumption, reduced power, metallic noises, and blue or black smoke from the exhaust pipe. Intake issues: If there is a problem with the vehicle's intake, it may cause engine pipeline blockage, and in severe cases, trigger the engine malfunction light. A dirty air filter that is not cleaned regularly can lead to intake problems. Exhaust issues: Exhaust faults can also cause the engine malfunction light to illuminate. The rear oxygen sensor, catalytic converter, exhaust camshaft, and bearing failures are all causes of exhaust problems, with the catalytic converter being the most common. Using leaded gasoline, lead or silicon-containing lubricant additives, physical damage to the catalytic converter, or faults in the engine fuel supply system can easily cause catalytic converter failure. Anti-theft system malfunction: If the vehicle's electronic anti-theft system malfunctions or the anti-theft controller does not match the engine electronic controller, the anti-theft system can also prevent the engine from operating normally, while the engine malfunction light illuminates. If the engine malfunction light comes on, follow these steps: First, check if the engine is running normally and if there are issues such as shaking or black smoke. If so, avoid restarting the engine. Especially note that if the red light is on, do not restart the engine under any circumstances. If the engine can be started, turn it off for 5-10 minutes, then without pressing the brake, press the start button once or turn the key halfway to the 'on' position without depressing the clutch. The vehicle will perform a self-check after powering on. Wait for 5-10 seconds and observe whether the malfunction light on the dashboard turns off. If the malfunction light remains on, visit a service station as soon as possible to identify the cause. The service station can use a portable diagnostic tool to read the fault codes, obtain fault information, and perform targeted repairs.
The engine warning light is on, and I've seen this many times in my over 20 years of driving. The most common issue is with the emission system, like a dirty or faulty oxygen sensor causing the computer to detect abnormal emissions and trigger the warning light. It could also be engine misfires due to old spark plugs or failing ignition coils, leading to incomplete combustion and the light coming on. Another possibility is insufficient fuel system pressure or abnormal fuel pump operation, such as a loose fuel cap allowing air to enter and affect the system. More complex issues might involve sensors like the crankshaft position sensor malfunctioning. First, check simple things—tighten the fuel cap and see if the light goes off. Then, use a scanner to read the trouble codes to pinpoint the exact issue. If the light is flashing, don’t hesitate—stop the engine immediately, as this indicates a serious problem like a misfire that could damage the engine. Ignoring it can lead to higher fuel consumption, excessive emissions, and increased wear. Don’t wait for a small issue to become a big one; get it checked at a professional shop for safety.
