“Check” icon in the car: what it looks like, what it means and when it lights up

The translation of the expression “check engine” in Russian literally sounds like “check the engine.” The “check” icon is on the dashboard of most modern cars, but its meaning remains unclear to many. Therefore, if this icon is yellow or orange engine icon - appears and does not disappear (or simply blinks), an inexperienced driver has a natural question: “what does this mean?” Next, we’ll try to find out the reasons why the check engine light came on on the dashboard of your car, as well as how to get rid of it.

Initially, this light indicated problems with the carburetor, but now that cars are equipped with full-fledged on-board computers, the message may indicate various malfunctions. For example, a “check engine” error may indicate problems with the quality of the air-fuel mixture or ignition faults, as well as many other things. Messages can be caused by both minor and critical failures.

Thus, when the “check engine” light is on, it is only clear that the ECU has detected a malfunction in one of the car’s systems. Only diagnostics can give a complete picture. Next, we will look at the main reasons why the check engine light is on and what needs to be done about it.

What does it look like

An illuminated check engine light on a vehicle looks like a yellow or red “video camera” without an exclamation point, with the words Check Engine displayed inside or next to it. The indicator lights up on the car's dashboard (on the display behind the steering wheel). A photo of a picture with a receipt icon in a car is presented below.

Check badge in the car

The yellow “Check Engine” icon means that the car owner needs to independently change something in the car control system or take the car to a service station.

A red indicator may indicate a serious breakdown. Driving by car is strictly not recommended. The car needs to be taken to the service station urgently.

If the engine light is on in the car, then there are definitely the following faults:

• low-quality gasoline or other fuel is poured into the tank;
• spark plugs have failed;
• the integrity of the ignition system coil winding is damaged;
• there is a short circuit in the engine;
• The residual oxygen sensor (lambda probe) stopped working;
• the injectors are clogged;
• the catalyst does not work.

The Check Engine icon only blinks intermittently in the following situations:

• When the engine triples (not all the fuel burns). The check sign in the car lights up when a spark is missed. Unburnt fuel is discharged through the exhaust manifold.
• In case of critical wear of the catalytic converter. As a result, the car cannot be used.
• If the engine ECU fails.

The exact cause of a car breakdown can only be found out by diagnosing the ECU with an OBD 2 scanner or at a service station.

Exhaust gas catalyst maintenance

The task of an automobile catalyst is to clean exhaust gases from toxic impurities, which is required by environmental standards. The element converts carbon monoxide and other hazardous substances into harmless compounds, so the exhaust becomes cleaner. And if the catalyst malfunctioned or was completely damaged, this will be displayed on the instrument panel in the form of a Check engine indication. Also, a breakdown may be accompanied by a decrease in vehicle power by approximately 2 times, which will worsen the previous acceleration dynamics.

The reasons for catalytic converter failure vary. The most common ones include the following:

• Lack of regular technical inspection.
• Damage to the oxygen sensor and untimely installation of a new one.
• Worn spark plugs.

If the last two elements fail, the carbon monoxide mixture remains harmful, full of toxic impurities. This composition leads to severe overheating and then damage to the catalyst.

If a part becomes faulty, you will have to stop driving the car because the motor will not be able to function normally and a corresponding notification will appear on the dashboard. In addition, catalyst wear will cause increased fuel consumption and reduce the normal thrust of the power plant.

Buying a new catalyst is an expensive investment, but it is inevitable. There are alternative solutions in the form of installing a flame arrester, but this option cannot replace a failed unit and it has disadvantages. Without experience in carrying out repairs, it is better not to start it yourself. Instead, the task should be left to a professional auto mechanic.

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What does it mean

Check Engine is translated from English as “check the motor (engine).” The error code is indicated as follows: P0102… P0616.

The first letter of the error code identifies one of the car systems in which the breakdown occurred. There can be 4 codes in total:

• P - gearbox and/or engine;
• U - CAN bus;
• C - chassis;
• B - airbags, electric windows, central locking.

The second character after the letter indicates the type of error. The breakdown can be general (the same for all OBD II engines) or specific (for a specific car).

When the check icon appears

The second character of the error code is indicated by the following numbers:

• 0 - OBD 2 code;
• 1, 2 — manufacturer code;
• 3 - Reserved SAE (reserve).

The third character of the error code is the car subsystem where the failure occurred. The following numbers may appear on the receipt icon in your car:

• 1, 2 - injector circuit, fuel pump, fuel tank or air supply system;
• 3 - ignition system;
• 4 — auxiliary system (control);
• 5 — car speed, idle;
• 6 - ECU and its external circuits;
• 7, 8 — gearbox;
• 9, 10 - reserve.

The fourth and fifth characters of the error code indicate its serial number.

How to redeem a badge

The Check Engine icon remains on the vehicle's dashboard as long as there are still error codes in the OBD system's memory. After the fault is repaired, the codes are erased using a diagnostic tool. You can also extinguish the check icon in the car by disconnecting the terminals from the battery (for 3-5 minutes).

The easiest way in this case is to use a personal scanner. There are quite a lot of similar devices on the market, and an inexpensive car scanner will cost less than one visit to a service station. For example, we can recommend the multi-brand diagnostic scanner Rokodil ScanX.

The advantage of this model is that it is compatible with most cars produced in 1993 with an ODB2 connector. The scanner connects to any iOS, Android or Windows device via Bluetooth. In addition to resetting errors with the scanner, you can carry out a full diagnosis of the car and fix the problem yourself. After diagnostics, the device will indicate the problematic element and display its error code with a detailed description. We will consider the most common error codes below.

What else do you need to think about?

We were able to describe several of the most frequently repeated cases of this signal lighting up. The engine designs of different cars differ, so there may be other reasons for the appearance of an alarm signal. It will be best for you and your car if computer diagnostics of all car systems is carried out. To do this, you can use the services of specialized centers, but some “advanced” drivers do this on their own.

Pay more attention to your “iron horse”, use only high-quality fuel and consumables, then you won’t have to worry about why the check light comes on when driving. And if you do see an “alarming” signal, do not rush to extremes, but delve into the problem and eliminate it.

Table of the most common error codes

To find out the error code, you need to do the following:

1. Turn off the car engine.
2. Look under the steering wheel and find the diagnostic connector.
3. Install the OBD 2 scanner into the found connector. If everything is done correctly, the indicator on the adapter will light up.
4. Pick up your smartphone and open Google Play Store.
5. Download, install and run the Torque program.
6. Open “Settings” on your phone, select the Bluetooth tab and find the Aut-Tech scanner.
7. In the window that appears, you must enter the password - 1234 (1111, 1234, 0000, 123456) and click on “OK”. The inscription “Authorized” will appear in the list.
8. Launch the Torque program.
9. On the smartphone screen, click on the button with a gear - this is “Settings” (or on the button on the phone body).
10. In the menu that appears, select “Settings”. In it you need to open the Connection section. Bluetooth (Wi-Fi) must be installed here.
11. Select the Device section. In the list, click on the Aut-Tech scanner.
12. Exit to the Torque program menu and click on Check Fault Codes. The error log will open.
13. Click on the search button (in the form of a magnifying glass). An error code will be displayed on the screen.

An overview table of common error codes with explanations is presented below.

Error Code Table

Once the error code has been deciphered, you can safely begin troubleshooting the problem yourself. If serious damage is detected, you must take your car to a service station.

In what situations can you reset errors yourself?

If the check icon is on in the car, then it is not necessary to immediately contact the service station. You can reset error codes yourself in the following situations:

• when refueling your car with low quality gasoline;
• if the car breakdown occurred due to a faulty fuel pump and its filter;
• in case of nozzle clogging;
• in case of failure of the ignition system;
• if the air supply system is broken.

You can also extinguish the “Check Engine” icon yourself if you have problems with car wiring, sensors and ECUs.

When filling the gas tank with low-quality fuel

Most often, the “Check Engine” icon lights up due to the presence of low quality fuel in the gas tank. After all, “diluted” gasoline is available at many gas stations.

Low quality gasoline clogs the fuel line and its parts. As a result, a malfunction such as tripping appears (the engine constantly stalls).

Refueling with low-quality fuel

To remove tripping, you need to drain gasoline (DF) from the entire system. Moreover, you will have to not only open the gas tank, but also remove it and wash it.

If the fuel pump and its filter are faulty

The “Check Engine” icon may also turn on if the fuel pump and its filter are faulty. To check the functionality of the pump, you need to stop the car and listen to the sounds of the engine running.

Everything is fine with the fuel pump if you hear a smooth hum (without clicking or pauses). If extraneous sounds are heard, then the pump must be removed and washed from the inside. You also need to clean the filter.

It would also be a good idea to check the pressure in the fuel rail. It should be equal to at least 3 atmospheres. If the pressure in the fuel rail is below 3 atm, you need to replace (clean) the filter or replace the old fuel pump with a new one.

If the injectors are clogged

If low-quality gasoline (DF) is poured into the gas tank, then over time the injectors become clogged. As a result, the engine begins to work intermittently.

To clear clogged injectors, you need to do the following:

1. Remove the injectors and disassemble them.
2. Remove the nozzles.
3. Install the nozzles into the washing stand.
4. Check their performance by applying different pressures.

As a result, the faulty nozzle is quickly cleared of debris. It can also be replaced with a new one.

Ignition system is faulty

The “Check Engine” icon may also indicate the failure of one or more spark plugs. To troubleshoot the problem, you need to do the following:

1. Carefully inspect the spark plugs.
2. Remove carbon deposits (if any).
3. Replace spark plugs if they are faulty.

Carbon deposits on spark plugs

Service station specialists advise changing not just one spark plug, but the entire set at once. This way you can avoid possible problems in the ignition system. Timely replacement of spark plugs is the key to the correct operation of the car engine and catalytic converter.

The air supply system is broken

The Check Engine icon also lights up if the throttle valve is faulty (clogged). To fix the problem, you will have to remove the throttle and clean it.

Service station specialists recommend cleaning the throttle valve using a specialized product (for example, Liqui Moly DrosselKlappen-Reiniger). But you can also use WD-40, acetone or carburetor cleaner.

Together with the throttle valve, the air filter pipe is also cleaned from blockages. If the air supply system is broken, the following signs of malfunction will appear in the car:

1. Increased consumption of diesel fuel (gasoline) and the level of carbon dioxide in the exhaust.
2. Reduced ride quality.
3. Reduced engine power.

If the air supply system malfunctions, poor acceleration dynamics are also observed. And in winter the car starts every other time. Malfunctions also appear due to improper installation of the filter when replacing it, or if it has not been replaced with a new one for a long time.

If you continue to drive a car with a faulty air supply system, then over the course of several months the engine will “eat” more and more gasoline (DF). The car owner needs to take his car to a service station as soon as possible or fix the problem himself.

If there are problems with wiring, sensors and ECU

More often, the “Check Engine” icon lights up on the car’s dashboard when the ECU fails or when the engine wiring is faulty. One of the sensors may also break.

After connecting the OBD 2 diagnostic adapter to the car dashboard, an error code will appear on your smartphone. After decoding, you need to find the broken sensor and check it with a multimeter. If there is no signal, the meter must be replaced.

Diagnosis of wiring faults is carried out in a similar way. Only after deciphering the error code is the wire ringing done. As a result, it will become clear which section of the wiring needs to be repaired.

Car wiring diagnostics

If a wiring fault is detected, service station specialists advise immediately changing the wire in the area where there is damage. After all, car owners often simply strip and insulate the damaged cable.

The Check Engine light may also come on if the engine ECU is faulty. Installing new software on the car control unit will quickly solve the problem.

Is it possible to drive a car if the Check Engine light is on on the dashboard?

If the Check Engine light suddenly lights up in your car, you first need to insert the key into the ignition and start the car. Let the car idle for 3-5 minutes.

After 3-5 minutes, you need to increase the engine speed. If no extraneous sounds (clicks) are heard or there are no pauses, then you can start moving towards the service station (first at 20-30 km/h).

If the car service is far away, you should do the following:

1. Stop the car.
2. Turn off the engine.
3. Open the hood.
4. Remove the negative terminal from the battery.

If, after re-igniting the engine, the Torque auto program does not show an error code, then the malfunction can be considered accidental. However, the car owner should contact the service station for advice.

The Check Engine light may come on while driving. If the icon appears after refueling at a gas station, then in most cases the fuel is clearly at fault.

After a breakdown occurs, it is recommended to drive to a branded gas station and fill the gas tank with high-quality fuel (gasoline). As the car moves further, there should be no strong dips, twitching or sudden decrease in engine power. Otherwise, the car owner should get to the nearest service station as quickly as possible (on his own or by calling a tow truck).

Checking the fuel tank cap

When trying to understand why the check engine light is on, car owners consider worst-case scenarios, but do not pay attention to minor breakdowns. These include loss of sealing of the fuel system due to deformation or improper fixation of the tank filler cap. With such a defect, the error icon may light up suddenly. If the system is not properly sealed due to air leaking through the cap, fuel consumption will increase and a Check Engine notification will appear on the dashboard.

If, after the indication lights up, the car does not lose its previous power, and there are no sound changes in the operation of the power plant (knocking, humming, creaking), you must perform the following actions:

• Check the gas tank for leaks. If the filler cap is damaged, it must be replaced.
• Check that the cover is securely fastened. If the cap is not tightened sufficiently, air will enter the fuel system, causing the indicator to light up. Just tighten it all the way and then continue driving. If you do everything correctly, the error will disappear after some time.

What can result from untimely repair and diagnostics of a car engine?

If the breakdown is not promptly repaired after the Check Engine light comes on, the following consequences are possible:

• Troubleshooting, engine shutdown.
• Systems failure.
• Increased consumption of diesel fuel (gasoline).
• Transmission overheating.
• Cylinder head deformation.
• ECU block failure. Its malfunction often leads to incorrect operation of car systems.

If the Check Engine light on the car's dashboard lights up, this indicates that there are faults in the car that need to be repaired immediately. To find a breakdown, you should diagnose the ECU with an OBD 2 scanner and find out the error code. Only after a preliminary check using the Torque program can you look for a mechanical problem.

Battery disconnect method

Disconnecting the battery is an old way to reset the check engine light. Here are three steps to clear the check using this method: Step 1: Disconnect the cables from the battery. At this point, you should use a wrench to unscrew the positive and negative cables.

Step 2: Discharge the remaining electricity. The next thing you should do is press and hold the car horn for about 30 seconds. This action will help drain the car battery.

Step 3: Wait and reconnect the battery. After disconnecting the battery cables and draining the remaining electricity, all you have to do is wait about 15 minutes and then plug the battery back in. Error codes will be cleared. (Note: This method may not work on some vehicles.) If after this procedure the “check” lights up again, this may mean that the problem is still much more serious.