10 Reasons Why the Check Engine Light Comes On

(Baonghean.vn) - The check engine light is the most general warning light among the lights on a car, because it is related to many machine parts. When the light is on and does not turn off on the dashboard, it is time to check the car's engine.

Below are 10 common problems that cause the car to display a check engine light, helping you "diagnose" the problem and take the car in for repair.

1. Damaged high voltage wire, power distributor

Depending on the type of vehicle, different ignition systems may be used to supply power to the spark plugs. When one of the components of the ignition system fails, it will cause misfires, incomplete fuel combustion, reducing the vehicle's performance and potentially damaging the exhaust filter.

2. Ignition coil failure

The ignition coil (also called the ignition coil) supplies high voltage to the spark plugs to create a spark. Constant engine heat can weaken or damage the ignition coil.

A faulty ignition coil will prevent the car from starting, if it is weak it will waste fuel and can lead to damage to the catalytic converter.

3. Wind sensor failure

The air sensor measures the amount of air entering the engine and the ECU calculates the appropriate amount of fuel to be injected into the combustion chamber. When this sensor is not working properly, it will cause an imbalance in the air and fuel ratio, reducing engine performance.

4. Exhaust gas recirculation system

Over time, dirt and soot build up and clog exhaust pipes. This causes the car to consume more fuel, lose power, and cause the check engine light to come on.

5. Broken fuel tank cap

In fact, the fuel cap is more important than you think. If it is cracked, damaged, or not sealed properly, fuel will evaporate and cause the entire fuel combustion system of the car to malfunction, leading to increased fuel consumption and emissions.

6. Improper installation of alarm devices

If you want to install an alarm device, you should decide before receiving the car so that the dealer can install the correct type. You should not buy and install it yourself because there are many types of alarm devices that may not be compatible with the devices on your car.

7. Oxygen sensor not working

The oxygen sensor measures the amount of unburned oxygen escaping from the exhaust and tells the ECU to adjust the amount of fuel injected. A damaged or non-functioning sensor can increase fuel consumption by up to 30%.

8. Fuel injector

Over time, the fuel tank will accumulate a certain amount of dirt and this can build up on the injector nozzles. Fuel lines and injectors with dirt build up are also one of the reasons why the check engine light comes on.

9. Fuel filter valve relay stuck

The EVAP system purge valve relay (which is a system that filters vapors released from the fuel tank or fuel injection system) controls the escape of gases from the fuel system. This relay operates in cycles and can become stuck, causing the valve to stay open.

10. Air filter control valve failure

This valve is part of the EVAP system. When the engine starts and warms up, the engine control unit (ECU) allows this valve to slowly open to allow some of the gasoline vapor from the charcoal canister to enter and be burned in the combustion chamber. The check engine light will illuminate when this airflow is more or less than the level set by the ECU.

Ngoc Anh

(Synthetic)