What to Do When the Engine Malfunction Light Comes On in a Car?
2 Answers
When the engine malfunction light comes on, follow these steps: First, check if the engine is running normally and whether there are issues such as shaking or emitting black smoke. If present, avoid restarting the engine. Note: Do not restart the engine if the light is red. If the engine can start, turn it off for 5-10 minutes. Without pressing the brake, press the start button once or turn the key halfway to the 'on' position without pressing the clutch. The car will perform a self-check after powering on. Wait for 5-10 seconds to see if the malfunction light on the dashboard turns off. If the light remains on, visit a service center as soon as possible. The service center can use a portable diagnostic tool to read the fault code, identify the issue, and perform targeted repairs. There are seven main reasons why the engine malfunction light may come on: Sensor Failure: Sensors such as coolant temperature, crankshaft position, air flow, intake temperature, and oxygen sensors may become damaged, have poor contact, or lose signal. This prevents the car's ECU from accurately obtaining engine data, triggering the malfunction light. Fuel or Oil Quality Issues: Using fuel or oil that does not meet the manufacturer's specifications may cause engine wear, leading to the malfunction light. Poor Combustion of Air-Fuel Mixture: Poor combustion can cause engine carbon buildup or knocking. The oxygen sensor detects this and reports it to the ECU, triggering the malfunction light. Issues such as faulty spark plugs, ignition coils, fuel pumps, or clogged fuel lines can lead to poor combustion. Turbocharger Problems: Issues with the intake boost line or turbocharger can also trigger the malfunction light. The most common issue is a damaged turbocharger, accompanied by symptoms like oil leaks, excessive oil consumption, reduced power, metallic noises, or blue/black smoke from the exhaust. Intake Problems: Clogged engine intake passages can trigger the malfunction light. A dirty or uncleaned air filter can cause intake issues. Exhaust Problems: Exhaust system failures, such as faulty rear oxygen sensors, catalytic converters, exhaust camshafts, or bearings, can trigger the malfunction light. The catalytic converter is the most common culprit. Using leaded gasoline, lead- or silicon-based oil additives, physical damage to the catalytic converter, or fuel system issues can cause catalytic converter failure. Anti-Theft System Malfunction: If the car's electronic anti-theft system fails or the anti-theft controller does not match the engine ECU, the engine may not function properly, and the malfunction light will come on.
When the engine warning light suddenly comes on, I don't panic because I've encountered it several times during my years of driving. Usually it's a minor issue, like a loose fuel cap or a faulty sensor. I'll check the dashboard to see if there are any other warning lights, then try to pull over safely and inspect under the hood for unusual smells or oil leaks. If nothing seems wrong, I'll drive gently to the nearest repair shop. Never ignore it—the light indicates the engine management system is alerting you, possibly about emissions, fuel system, or electrical issues. Continuing to drive aggressively could worsen the problem, waste fuel, or even damage the engine. Last time my light came on, it was due to a dirty oxygen sensor, which was fixed with a simple cleaning. In short, timely action is crucial—don't compromise safe driving.
