What Causes the Engine Fault Indicator Light to Illuminate?
2 Answers
The reasons for the engine fault indicator light to illuminate are as follows: 1. Poor gasoline quality can lead to incomplete combustion of the air-fuel mixture in the cylinders, causing the fault light to illuminate and also easily leading to carbon deposits. 2. Carbon deposits in the intake tract and on the top of the pistons can result in poor atomization, leading to incomplete combustion and triggering the fault light. 3. During cold starts, especially when the temperature drops sharply, the fault light may illuminate due to the ECU's temperature correction issues. However, it will stabilize once the temperature drops to a certain level without fluctuations. 4. Excessive engine mileage can weaken the spark plugs' performance, causing the fault light to illuminate. 5. Excessive carbon deposits can make ignition difficult, leading to reverse breakdown of the ignition coil and causing poor ignition, incomplete combustion, and illumination of the fault light. A distinct characteristic of this phenomenon is severe and persistent engine shaking when the ignition coil is faulty. If the shaking is not persistent, the ignition coil can generally be ruled out. 6. Advanced vehicle age and mechanical wear can degrade engine performance, resulting in the fault light illuminating. 7. Faults in certain sensors or the ECU itself can cause the fault light to illuminate.
Last week, my car's check engine light came on while I was driving on the highway, which really made me nervous. I immediately pulled over at a service station. After inspection, it turned out that the spark plugs were severely worn, affecting ignition performance and causing the computer to misjudge the fault. Such issues are quite common—for example, a dirty oxygen sensor can reduce fuel efficiency, a clogged fuel pump can affect fuel supply, and even a loose gas cap can trigger a vacuum leak signal. The light coming on is like the vehicle 'sounding an alarm.' If minor issues are ignored, they can escalate into major repairs, such as costly catalytic converter damage. I recommend developing regular maintenance habits, like changing the oil and checking spark plugs every 5,000 kilometers, to prevent most faults. Also, keeping a small OBD scanner in the car allows you to scan trouble codes when the light comes on, pinpointing the issue accurately before repairs—saving money and peace of mind.
