The check engine light on your car is often seen as a frustrating and mysterious warning signal, but it’s actually your car’s way of communicating with you. This little light has the ability to alert you to a wide range of issues, but can the light turn off on its own?
In case of a transient issue, the check engine light may reset itself between engine starts. Most of the time, the indicator will return the next time the engine is started.
In this guide, we’re going to go over how the check engine light works, what problems the check engine light indicates, and what you should do when the light turns on.
How Does the Check Engine Light Work?
A car’s check engine light is a warning signal that there may be a problem with the vehicle’s emissions system. The onboard computer, also known as the engine control module, controls this light (ECM).
The ECM receives input from a variety of sensors throughout the vehicle, including oxygen sensors and mass air flow sensors. These sensors monitor a variety of factors that can affect emissions, such as fuel mixture, engine temperature, and engine performance.
If the ECM detects that any of the input signals are outside of the normal range, the check engine light will illuminate to warn the driver of a potential problem. Furthermore, the ECM may set a trouble code, which is a numerical code that aids in the diagnosis of the specific issue that is causing the light to illuminate. These codes, however, are frequently generic and do not indicate the precise cause of the problem.
What Does Check Engine Light Indicate?
Here is a non-exhaustive list of problems the check engine light will pick up.
1. Faulty catalytic converter
Before they are released into the atmosphere, harmful pollutants in the exhaust are converted into less harmful substances by the catalytic converter. When the catalytic converter fails, the engine runs poorly and emits more pollutants, causing the check engine light to illuminate. In some cases, debris can clog the catalytic converter, resulting in decreased engine performance and the illumination of the check engine light.
2. Faulty oxygen sensors
An oxygen sensor, also known as an O2 sensor, is an emission control system component that measures the amount of oxygen in the exhaust gas. When the oxygen sensor fails or becomes contaminated, it can send false readings to the ECM, causing the engine to run rich or lean. This can have a negative impact on the vehicle’s performance, fuel efficiency, and emissions, resulting in the check engine light turning on.
3. Bad spark plugs
Spark plugs are responsible for generating an electrical spark that ignites the air-fuel mixture that is contained within the cylinders of an internal combustion engine. It is possible for spark plugs to fail or wear out over time, which can result in misfires within the engine. These misfires lead to a decrease in performance, as well as a reduction in fuel efficiency and an increase in emissions. Because of this, the check engine light might turn on, which is a warning sign that there is a potential issue.
4. Bad ignition coils
The ignition coil is responsible for converting the low voltage of the battery into the high voltage that is necessary to ignite the air-fuel mixture that is contained within the cylinders of the engine. It is possible for an ignition coil to fail or become damaged, which can result in misfires in the engine as well as the illumination of the check engine light.
Misfires can have a detrimental effect on the performance, fuel efficiency, and emissions of the vehicle, leading to a reduction in the vehicle’s overall drivability and an increase in emissions.
5. Faulty mass airflow sensor
A mass airflow sensor (MAF). is used to determine how much air is being drawn into the engine at any given time ECM makes adjustments to the amount of fuel that is supplied to the engine based on the information that it receives, thereby ensuring that the air-fuel mixture is optimized for maximum performance and efficiency.
If the MAF sensor fails or becomes contaminated, it is possible for it to send false readings to the ECM. This can cause the engine to run too rich or too lean, as well as activate the “check engine” light.
6. Loose gas cap
The gas cap, which also goes by the name fuel filler cap, serves to seal the fuel tank, thereby preventing fuel from leaking out and evaporating. If the gas cap is missing, damaged, or even just slightly off, the pressure in the fuel system will drop, which will result in the warning light for the engine coming on.
Can the Check Engine Light Turn Itself Off?
The check engine light may turn off on its own in some cases. This can occur if the issue that triggered the light was only temporary, such as a loose gas cap or a temporarily high emissions reading. If the problem is resolved and the conditions return to normal, the check engine light will turn off on its own after some time and driving.
However, in many cases, the check engine light will not turn off on its own, and the problem must be diagnosed and repaired. Ignoring a check engine light can result in additional damage to the engine and other components, as well as a decrease in vehicle performance, fuel efficiency, and emissions. Some problems, such as a faulty catalytic converter or a failing oxygen sensor, can be serious and necessitate immediate attention.
Even if the check engine light goes out on its own, it’s still a good idea to have the vehicle checked by a professional mechanic to make sure there aren’t any underlying issues that need to be addressed. This can help prevent more serious and costly problems in the future while also ensuring your vehicle’s health and performance.
What to Do When Nothing Appears Wrong
Even if your vehicle appears to be in good working order, your engine light could be illuminated for a variety of reasons. Perhaps something is wrong and you are unaware of it. Some of the most common causes of an illuminated “engine light” include a loose gas cap, a need for an oil change, and a problem with your engine’s emission system.
Can You Drive When the Check Engine Light Is On?
It is possible to drive a car with the check engine light on, but it is not recommended. The check engine light indicates that there is a problem with your vehicle’s engine or emissions system that must be resolved.
Driving a car with a check engine light illuminated can cause additional damage to the engine and other components and negatively impact the vehicle’s performance, fuel efficiency, and emissions.
If the check engine light illuminates, the problem must be diagnosed and repaired as soon as possible. Some problems, such as a faulty catalytic converter or a failing oxygen sensor, can be serious and necessitate immediate attention. Ignoring the check engine light can lead to more serious and costly problems in the future, as well as a decrease in the vehicle’s resale value.
Furthermore, some states and municipalities have laws that make driving a vehicle with a lit check engine light illegal because it emits excessive pollutants and harms the environment. If you must drive a car with a lit check engine light, have it diagnosed and repaired as soon as possible.