Reasons why the Check Engine light comes on in a car and how to fix it.
The Check Engine light illuminates when there is a fault in the car's engine or related systems, so what should you do then?
What is the Check Engine light?
The Check Engine light indicates a fault when the car's engine or related systems malfunction, and it's usually located in the instrument cluster behind the steering wheel. This light is yellow, and the Check Engine symbol on the car looks quite similar to a goldfish, so the Check Engine light is also often referred to as the "goldfish error."
The engine control unit (ECM - Electronic Control Module, located within the ECU) directly receives information from the vehicle's sensors, then processes it and sends commands to control the entire operation of the engine, such as controlling fuel injectors, valve opening, ignition timing, etc.
When the ECM detects that the sensor readings are different from normal or that there is a signal loss, the ECM will instruct the Check Engine light to illuminate to notify the driver.
Reasons why the Check Engine light comes on.
When the car starts, all the warning lights on the instrument cluster usually illuminate and then turn off, indicating that the system has started and is functioning normally. However, if there is an engine fault, the Check Engine light will illuminate or flash continuously without turning off.
This Check Engine light error usually occurs due to the following reasons:
Spark plug:A check engine light (or spark plug) is usually caused by faulty spark plugs, such as worn or dirty spark plugs, damaged spark plug connectors, or faulty high-voltage wires. These issues can cause the spark plugs to produce a weak or ill-timed spark, significantly affecting the combustion of the air-fuel mixture, reducing engine efficiency, and leading to engine vibration, jerking during acceleration, and stalling while driving.
Ignition coil:The ignition coil in a car is typically responsible for generating a high-voltage current for the spark plug to produce a spark that ignites the fuel-air mixture in the engine cylinder. If the ignition coil fails, it will affect the spark plug, causing the check engine light to illuminate yellow.
Fuel injectors:Fuel injectors help deliver fuel to the combustion chamber. If the injectors operate for many days without cleaning, they can easily become clogged due to deposits and rust, seriously affecting engine performance. When the ECM detects a faulty injector, the car's Check Engine light will illuminate to warn the driver.
Fuel vapor control system:The fuel vapor control system is responsible for absorbing fuel vapors as they pass through the filter into the combustion chamber, preventing them from escaping from the fuel tank. If this system malfunctions, it will trigger the check engine light. If the fuel cap is not properly closed, the car will also display a check engine light.
Therefore, if you see the check engine light come on, one of the first steps you should take is to check the fuel cap.
Exhaust gas recirculation system:The exhaust gas recirculation system's function is to return exhaust gases to the intake air to reduce NOx concentrations. After prolonged operation, the exhaust gas recirculation control valve or the piping system may become clogged due to dirt and soot buildup, at which point the ECM will illuminate the check engine light to indicate a problem.
How to fix the Check Engine light error on your car.
When the Check Engine light comes on, if the car has minor engine problems, it may still run normally. However, you shouldn't be complacent because if not fixed promptly, the car's problems could become more serious.
For safety reasons, the best course of action at this time is for the driver to operate the vehicle at speeds below 40 km/h and then take it to a garage for immediate inspection.
If the Check Engine light is flashing continuously, it indicates an emergency situation; the engine may be overheating or the catalytic converter may be overheating. Continuing to drive could seriously damage the vehicle's operating system, or even cause a fire. Therefore, it is best to find a safe place to stop the car and call for roadside assistance to tow it to a garage for inspection.