What is a check engine light and how does it work?

Tips

Artur Owczarek

Brand Product Manager Moje AutoHe has been involved in the automotive industry for years. He is passionate about cars and detailing. On his blog, he shares his knowledge and experience, offering tips on how to effectively care for your car and extend its life.

What is a check engine light and how does it work?

Check engine light plays a key role in electronic dashboard every car. It is a tool that notifies the driver of potential problems related to the engine or exhaust emissions. Its operation is based on self-diagnostic system, which constantly monitors vehicle operation. As soon as the ignition is turned on, the light illuminates momentarily, indicating its proper operation, and then turns off once the engine is started.

When the check engine light comes on while driving, it means the on-board computer has detected a problem. This could be:

• a minor defect, such as a damaged sensor,
• a more serious fault that requires urgent intervention.

Ignoring the warning light can lead to significant engine damage. Therefore, it is extremely important to have your car diagnosed as soon as possible. The light's operation closely interacts with OBD-II system, which records and stores error codes, allowing mechanics to locate problems more easily.

It is also worth emphasizing that the check engine light may indicate various faults in the vehicle's electronic systems. To ensure proper engine operation and reduce pollutant emissions, you should treat the illumination of this warning light as a serious signal to act.

How do OBD-II and on-board diagnostics work?

OBD-II system, or On-Board Diagnostics II, is an automotive standard introduced in 1996. Since 2001, its use has been mandatory for all newly manufactured cars. The system's primary purpose is to monitor engine performance, fuel systems, and exhaust emissions. OBD-II allows for early detection of potential faults.

OBD-II diagnostics works by remotely accessing information from the vehicle's on-board computer. This system records error codes, which can be read using an OBD2 diagnostic scanner. Although the operation itself is simple, interpretation of these codes requires some technical knowledge. Vehicle documentation usually includes tables that help in understanding the errors.

Using OBD-II significantly speeds up the fault identification process. After connecting the scanner, the system instantly identifies any irregularities in the operation of the engine and other components. This allows mechanics to quickly determine the cause of the warning light. "check engine" and plan appropriate corrective steps.

Moreover, vehicle owners They can use an OBD2 scanner themselves, allowing them to constantly monitor their car's technical condition. With the right apps, users can detect and analyze errors, which in turn helps keep their vehicle in good condition and prevent more serious breakdowns.

What do the colors and states of the check engine light mean?

Check engine light colors provide important information about the vehicle's condition.

• a yellow or orange light indicates a problem that should be investigated as soon as possible, although it is not a reason to stop the car immediately,
• this may suggest sensor damage,
• Although this does not pose a threat to driving safety, diagnostics should still be considered.

Red light indicates a more serious failure that requires immediate stopping of the vehicle.

• neglecting this warning may result in serious engine damage,
• If the light is flashing, there are most likely critical problems, such as misfire, which require a quick response,
• In such situations, it is worth considering calling roadside assistance.

Interestingly, the light may go out after the problem is resolved. That is why it is so important to monitor its condition. Regularly addressing technical issues significantly impacts the durability and reliability of your vehicle. In addition, it is also worth paying attention to other indicators on the dashboard, which will help you better understand what actions may be necessary in a given situation.

What are the most common causes of the check engine light coming on?

The most common causes of a check engine light are related to various systems and parts in your vehicle. Here are some of the most important reasons why this light might come on:

• broken lambda probe – this sensor is responsible for monitoring the oxygen level in the exhaust gases, if it is damaged, it may disturb the operation of the fuel system and increase pollutant emissions,
• catalytic converter problems – the catalytic converter plays an important role in processing harmful substances in exhaust gases, its failure leads to increased pollutant emissions,
• fault EGR valve – the exhaust gas recirculation (EGR) valve is crucial in reducing nitrogen oxide (NOx) emissions, its failure can cause serious emission problems,
• fuel injectors – damage to these components affects the quality of the fuel-air mixture, which often results in the warning light coming on,
• engine sensor failure – damage to sensors, such as the crankshaft or camshaft, may also cause the warning light to come on,
• problems in the ignition system – damaged spark plugs or coils can make starting the engine more difficult,
• faults in exhaust and fuel emission systems – problems with these systems, such as incorrect fuel pressure, can also activate the warning light,
• loose fuel filler cap – even minor defects, such as a poorly closed fuel filler cap, can cause the check engine light to come on,
• fuel quality – low fuel quality significantly affects the engine operation and may cause the warning light to come on,
• LPG installation – in vehicles with a gas installation, problems with the fuel mixture may occur, which also leads to the warning light coming on.

Each of these components is essential for the proper operation of the vehicle. Therefore, regular inspections and maintenance are very important. When the light comes on, quick diagnosis is recommended to avoid more serious engine faults.

How to read error codes in the OBD-II system?

To read system error codes OBD-II, you need a diagnostic scanner OBD-IIThe process is easy and consists of a few simple steps:

1. connect the scanner to the socket OBD-II, which is usually located under the dashboard, near the steering wheel,
2. turn on the ignition but do not start the engine,
3. in the scanner menu, select the option to read error codes,
4. the scanner will connect to the on-board computer and download the collected fault codes.

After this step, it's worth consulting your vehicle's documentation or database. Remember that error codes can indicate various problems, such as:

• faults in the fuel system,
• sensor errors,
• issues related to the emission system.

Based on the codes you've read, determine what repair actions are necessary. While self-diagnosis is helpful, for more serious problems, it's best to seek professional help.

OBD-II scanner greatly simplifies the problem identification process, allowing you to quickly deal with engine-related difficulties. Accurately reading error codes is crucial to ensuring your vehicle is operating properly and minimizing the risk of costly repairs in the future.

How to clear errors and turn off the check engine light?

Erase errors and turning off the check engine light can be carried out in various ways, but none of them eliminates the real causes of the problems.

One of the most effective solutions is to use the services of a professional workshop. The mechanic will connect the car to a diagnostic computer, which allows for the erasure of stored error codes. After proper repair, the light should go out permanently.

Another option is to act independently, which involves:

• disconnecting the battery for a few minutes,
• resetting the on-board computer,
• temporarily turning off the indicator light,
• the check engine light returns after restarting the engine.

However, it is worth remembering that frequent deletion of errors without repair can lead to more serious engine problems and significantly higher repair costs. Therefore, it is crucial identifying and removing the source of the problemto provide a long-term solution. Investing in good diagnostics will help avoid future problems and ensure the proper functioning of the vehicle.

How should you react if the check engine light comes on while driving?

When the check engine light on your dashboard comes on, it's important to react quickly. Keeping a cool head and assessing the situation can make all the difference in the safety and condition of your vehicle.

First, focus on the color of the lamp. If you see yellow and/ or orange signal, you can continue driving, but remember to check the technical condition of the car as soon as possible. First of all, verify:

• fuel level,
• make sure the filler cap is properly closed,
• whether the door is closed tightly.

After these steps, it is worth going to a mechanic to perform a thorough diagnostics.

In case of red and/ or flashing When the warning light comes on, the situation becomes more serious. This is a signal that you should stop the vehicle immediately and call for roadside assistance. Ignoring this warning can lead to serious engine damage, and repairs can be extremely expensive. Therefore, in such situations, it's best not to delay.

Any unintentional delay in repairing faults may expose you to even higher expenses. It is important to visit a workshop as soon as possible and discuss the situation with a specialist. Regular inspections and quick response to any signals can effectively minimize the risk of serious engine failures.

What are the consequences of ignoring the check engine light?

Ignoring the check engine light is a serious mistake that can lead to many problems, both technical and financial. An unnoticed signal can lead to engine damage, and problems that seem trivial at first glance can, in the long run, result in serious engine seizure or other costly breakdowns.
We must also not forget about the risk of serious damage to the fuel system. For example, damaged injectors typically result in higher fuel consumption, which in turn reduces your vehicle's performance. Other issues, such as a blocked catalytic converter in the exhaust system, can negatively impact engine performance, leading to even more expensive repairs.
Moreover, you may encounter difficulties during technical inspection. Problems that cause the check engine light to come on can affect emissions test results, making vehicle registration problematic.
Benefits of responding to the check engine light:

• reducing the risk of costly failures,
• fuel savings,
• improving vehicle performance,
• easier passage of technical inspections,
• longer engine life.

By responding to the check engine light and regularly maintaining your vehicle's technical condition, you have the opportunity to save money, as well as ensure greater safety and a longer life for your car.

How do I prevent the check engine light from coming on again?

To avoid the check engine light coming on, Regular vehicle diagnostics and prompt repair of any faults are crucial. It's worth paying attention to key engine components, such as:

• sensors,
• spark plugs,
• ignition coils,
• fuel injectors,
• condition of the exhaust system.

Regular technical inspections, in which these components are controlled can significantly reduce the risk of problems occurring. For example, when lambda probe not working properly, This can lead to disturbances in the fuel system, which increases exhaust emissions and may cause the warning light to come on.

Fuel quality is also crucial. Using low-quality fuel negatively impacts engine performance, increasing the risk of the warning light coming on. Furthermore, regular monitoring of the exhaust emissions system is crucial; any faults in this area can lead to serious problems.

After removing the cause of the light, it is worth clearing the error codes using OBD-II diagnostic scanner. This step after the repair has been completed will help avoid future complications and ensure that the light does not come on again. Careful attention to the technical condition of the vehicle and a quick response to any irregularities can significantly increase the reliability of your car.

How do LPG installation and fuel quality affect the check engine light?

In cars with LPG installation, the indicator light "check engine" often signals difficulties related to:

• fuel mixture,
• ignition.

LPG differs from gasoline, which can impact the combustion process. Additionally, poor-quality fuel and incorrect gas system settings, such as:

• used filters,
• injectors,

can contribute to unstable engine operation. In such situations, the warning light comes on, indicating the need for computer diagnostics.

When the warning light comes on in an LPG-powered car, it's a good idea to switch to petrol as soon as possible, if the system allows it. The next step should be consulting a gas systems specialist. Ignoring these warnings can lead to serious engine damage and expensive repairs.

Fuel quality should also not be underestimated. Using low-quality fuel can result in carbon buildup in the injection system, which can lead to damage:

• lambda probes,
• catalyst.

In such cases, the indicator light "check engine" lights up, indicating that the vehicle requires diagnosis and possible servicing. regular check-ups i attention to fuel quality can help the engine run better and reduce the risk of the warning light coming on.

Moje Car Engine cleaner

Where to buy View product

My Car Engine Self Start Moto Start

Where to buy View product

My Auto Engine Doctor – engine regenerator

Where to buy View product

When should you have your car towed to a workshop after the light comes on?

Getting your car towed to a repair shop is crucial in many situations, especially when the check engine light comes on. Here are some situations that require a quick response:

• Red or flashing light: This signal indicates a serious problem with the engine,
• Loss of power or rough engine operation: If your car starts to jerk, lose power, or runs erratically, it's time to consider towing,
• Difficulties in fault diagnosis: When the yellow light is on continuously and the source of the problem is unclear, it is worth consulting a specialist,
• Flashing light in LPG vehicles: In the case of cars with a gas installation, a flashing light indicates a serious problem,
• Exhaust system or turbocharger failure: Problems with these systems can lead to even more engine problems.

Towing in these circumstances helps reduce the risk of serious breakdowns and associated repair costs. By taking care of the technical condition of your vehicle, you increase safety and reduce expenses for future repairs.

How to prepare your car for a technical inspection when the check engine light is on?

To effectively prepare your car for a technical inspection, especially when the check engine light is on, it's worth taking a few key steps. First, before visiting the workshop, perform computer diagnostics. This step will help you understand why the light came on. Using the OBD-II system, you can read error codes, which will make it much easier to locate potential problems.

Another important element is focusing on basic controls. Check if:

• the oil level is appropriate,
• the windshield washer fluid level is adequate,
• the door is closed properly,
• the trunk lid is closed properly.

Don't forget that Any faults related to the exhaust, ignition, and fuel systems should be repaired. Damaged fuel injectors or sensors should be repaired. is crucial for the proper functioning of the engine. After the repairs are completed verify errors using a diagnostic scanner, and the result of this process will be to reset the control.

Regular technical inspections can significantly extend the life of your vehicle. They help avoid serious problems that can arise when the check engine light comes on, ensuring your car runs smoothly.