What Are the Reasons for the Engine Malfunction Light to Illuminate?
2 Answers
There are primarily 7 reasons for the engine malfunction light to illuminate: Sensor malfunction: The sensors referred to 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 combustion of air-fuel mixture: Poor combustion can lead to engine carbon deposits or knocking. Once detected by the oxygen sensor and reported to the ECU, the malfunction light will illuminate as a warning. Issues such as spark plug failure, ignition coil failure, fuel pump failure, or fuel line blockage can all cause poor combustion of the air-fuel mixture. Turbocharging problems: The intake turbocharging pipeline and turbocharger can also cause the engine malfunction light to illuminate. 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 problems: If the vehicle's intake system malfunctions, it may lead to engine pipeline blockage, and in severe cases, trigger the engine malfunction light. A dirty air filter that is not cleaned regularly can cause intake problems. Exhaust problems: Exhaust system failures can also trigger the engine malfunction light. Common causes include rear oxygen sensor failure, catalytic converter issues, exhaust camshaft and bearing failures, with the catalytic converter being the most frequent culprit. Using leaded gasoline, lead or silicon-based lubricant additives, physical damage to the catalytic converter, or fuel supply system failures can easily lead to catalytic converter problems. Anti-theft system malfunction: If the vehicle's electronic anti-theft system fails, or if the anti-theft controller does not match the engine electronic controller, the anti-theft system can prevent the engine from operating normally and trigger the engine malfunction light. If the engine malfunction light is on, follow these steps: First, check if the engine is running normally and look for symptoms like shaking or black smoke. If present, avoid restarting the engine. Particularly, do not restart if the red warning light is on. 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 enter self-inspection mode after powering on. Wait for 5-10 seconds and observe if the malfunction light turns off. If the light remains on, visit a service station as soon as possible for diagnosis. The service station can use a portable diagnostic tool to read the fault code, identify the issue, and perform targeted repairs.
Last time my car's engine warning light came on, I did some research and found there are quite a few possible causes. The most common issue is faulty sensors - for example, an aging oxygen sensor can trigger the light when it detects excessive emissions. The ignition system is another major culprit; worn spark plugs or faulty ignition coils can cause engine instability. Don't overlook the fuel system either - clogged fuel injectors or insufficient fuel pressure can lead to incomplete combustion. For emissions, a broken catalytic converter or exhaust pipe leaks can trigger warnings. It could also be an ECU software error or loose wiring. I recommend first using an OBD scanner to read the trouble codes for preliminary diagnosis, rather than replacing parts randomly and wasting money. Address the issue early to prevent engine damage and reduce fuel consumption.
