What is the problem when the engine light is on?
2 Answers
The reasons for the engine light being on are as follows: 1. Sensor issues: Sensors include water temperature, crankshaft position, air flow, intake temperature, oxygen sensors, etc. When these sensors are damaged, have poor contact, or signal interruption, the car's ECU cannot accurately obtain engine data, which will cause the engine fault light to illuminate. 2. Turbocharging issues: The intake turbocharging pipeline and turbocharger can also cause the engine fault light to illuminate. The most common issue is turbocharger damage, accompanied by symptoms such as oil leakage, high oil consumption, reduced power, metal noises, and blue or black smoke from the exhaust pipe. 3. Exhaust issues: Rear oxygen sensor, three-way catalytic converter, exhaust camshaft, and bearing shells. The most common issue is the three-way catalytic converter failure causing the engine fault light to illuminate. Using leaded gasoline, lead or silicon-containing lubricant additives, physical damage to the catalytic converter, and engine fuel supply system failures are some factors that can easily cause three-way catalytic converter failure. 4. Anti-theft system: If the car's electronic anti-theft system malfunctions, or if the anti-theft controller does not match the engine electronic controller, the anti-theft system can also cause the engine to not work properly, along with the engine fault light illuminating.
I was quite worried the last time my engine light came on because it usually indicates an issue with the engine management system. The most common causes could be a faulty oxygen sensor, which monitors emissions; or a loose gas cap, causing fuel vapor leakage; or even aging spark plugs leading to unstable ignition. Any of these can trigger the light. If the light is flashing, it’s even more dangerous, indicating engine misfire, which needs immediate attention. I remember that time I had a friend help me use an OBD scanner to check the trouble code, and it showed P0420. Later, replacing the catalytic converter fixed the issue. It’s best not to ignore this light while driving and avoid letting it stay on for too long to prevent further damage. I recommend finding a professional repair shop for a full diagnosis as soon as possible to stop small issues from becoming big problems.
