Most drivers are familiar with yellow icon a car engine that lights up when the engine or exhaust system malfunctions. In the descriptions of the instrument panel the indicator is called "check engine" (translation: “check engine”), it is used to generally indicate faults.
How to diagnose it yourself?
You can purchase a portable and inexpensive ELM 327 scanner.
By spending about 1,000 rubles on a portable scanner, you can diagnose the engine management system yourself.
By spending about 1,000 rubles on a portable scanner, you can diagnose the engine management system yourself.
It plugs into the OBD-II connector. You need to install a program for communicating with the car on your smartphone (you can use one of the free ones, they also work). By connecting the scanner to a smartphone via Bluetooth or Wi-Fi, you can read errors recorded by the control unit.
TOP 10 reasons why the check engine light came on
- The fuel tank cap is open . Check if it is closed tightly.
- Bad gasoline . The system can respond to fuel quality. The solution would be to drain the gasoline and fill it with better quality.
- Oil level . First of all, check its level with a dipstick. Also look for cracks in the block and oil leaks.
- Problems with the fuel pump or strainer in the tank. Check that the pump runs smoothly and does not make any unusual sounds.
- Dirty injectors . Eliminated by cleaning the injectors.
- Faulty high voltage wires or coils.
- Problem with spark plugs . The icon also lights up if there are problems with the spark plugs. It is worth checking the performance of the spark plugs and, if necessary, replacing them.
- No spark in one of the cylinders.
- The lambda probe is faulty . The problem can only be eliminated by replacing this unit with a new one or installing a blende; occasionally cleaning helps.
- Catalyst failure . Also solved by replacing the catalyst.
Only the main reasons and ways to solve them are listed here. In fact, there are many more of them. Diagnostics of the on-board computer, which controls all vehicle systems, can give a more complete picture of the current situation.
Check engine is not hidden on the dashboard of the Madza CX-5
Check engine on the Peugeot Partner panel is hiding in the left corner
Replace the mass air flow sensor
The mass air flow sensor regulates the amount of air that must be added to the gasoline mixture for optimal combustion of the fuel. This sensor constantly reports data on the amount of oxygen supplied to the car's computer. A faulty mass air flow sensor increases this fuel consumption and also increases the level of CO2 in the exhaust gas, thereby reducing engine power and smoothness. Also, if the sensor is faulty, poor acceleration dynamics are observed. In cold weather, a car with a faulty sensor has difficulty starting.
What are the reasons for the failure of the mass air flow sensor: -Most failures of such sensors occur due to improper installation of the air filter during its scheduled replacement. Also, if you do not regularly change the air filter, as required by the vehicle maintenance regulations recommended by the automaker, the mass air flow sensor may fail.
What needs to be done: -Theoretically, you can, of course, drive for a long time with a broken mass air flow sensor (several weeks or months). But you yourself will soon notice that the longer you drive, the more fuel consumption increases. Replacing a sensor in a car service is not so expensive, since this work itself does not take much time and is quite simple. Its main expenses are related to the cost of the sensor itself, which for some car models can cost from 11,000 to 14,000 thousand rubles if it is an original sensor, or up to 6,000 thousand rubles if it is an analog substitute. Replacing the sensor yourself is very simple. But, due to the low cost of the work itself to replace the sensor, you can entrust this work to an ordinary auto mechanic at a car service center. Remember, friends, that it is necessary to regularly change the air filter, observing the established maintenance regulations for the car!
What to do if the check engine light comes on
If while driving the Check Engine error is highlighted on the car panel, then it is necessary to quickly perform a detailed diagnosis of all components of the car. It will give a general assessment of the condition of the parts, which will help to quickly diagnose the problem and fix it.
Table of common error codes
A complete table of error codes in Russian allows you to quickly find faults. If your scanner does not translate them into Russian, then you can save this list and use it if necessary.
What do you do when this light comes on?
The translation of the expression Check Engine indicates the need to check the engine, that is, the electronic control system has detected some problems and informs the driver about it. Its operation is designed in such a way that when you turn the key in the ignition switch, the warning light should light up for a while and go out. At this time, all power unit systems are diagnosed, and an extinguished lamp indicates the absence of any problems.
Today, absolutely all powertrain systems are under electronic control; this is achieved by installing many different sensors. Based on their readings, the unit forms the composition of the air-fuel mixture, sets the ignition timing, controls the composition of exhaust gases and other important parameters. Based on this, we can conclude that there are quite a few reasons why this signal appears.
The check engine light is on - what should I do next?
You can try to find out the reason yourself by counting the number of blinks of the “check” and check the technical documentation for the designation of such an error code. For different cars there are different intervals between flashes and different codes by which they are interpreted.
Most of the errors that the indicator tells you about are not critical . You can perform diagnostics in two ways - yourself and by visiting a service station. The fact is that to obtain information in this case, you need special equipment or at least software for a smartphone.
But first of all, you need to find out how the car’s behavior changed after the error appeared. This is done in order to determine whether it is possible to drive with the check engine light on the panel, or whether it is better not to do this so as not to aggravate the problem.
| Car behavior | Icon is lit continuously | The check is blinking |
| Engine power and throttle response remain the same | You can keep moving | |
| No additional warning lights came on on the instrument panel. | ||
| The engine has become less responsive, the speed does not rise above a certain value (engine operation in emergency mode) | You can continue moving | The movement cannot be continued |
The car suddenly changed its behavior:
| The movement CANNOT be continued. | |
Along with the check engine icon, another indicator came on:
| ||
When does the check engine light come on?
We find out the reason why the check light is on
The error code can be read using a laptop with special software. The computer is connected via a cable to the machine's ECU and diagnostics are carried out. Also, using a laptop, you can enter additional external commands into the control unit or correct (reset) errors that appear.
A simpler method is to download an ECU communication and analytics program to your Android smartphone (for example, TORQUE, it has free and paid versions). And a Bluetooth adapter (car scanner) is connected to the electronic unit, which allows you to read information from the device. If you don’t have a laptop or you simply don’t want to bother installing additional software, you can delegate the described procedures to service station workers. They have all the necessary equipment and programs.
It must be remembered that each car (and sometimes each ECU on the same cars, but different years of manufacture) has a different list of error codes . Therefore, after receiving the information, you must have a standard set of diagnostic error codes (Diagnostic Trouble Code - DTC). You can find it in additional literature on diagnostics or on the Internet (for example, on thematic forums dedicated to your car model).
Another common cause for injection engines is problems with the injectors. In particular, the appearance of a significant amount of sediment on them. The solution to this problem is to clean the injectors. If problems occur with spark plugs, injectors, or the activated check engine indicator, the following symptoms may occur:
- weak engine thrust;
- high fuel consumption;
- jerks when accelerating or unstable operation of the engine;
- “floating” engine speed at idle.
The next step is to check the pressure in the fuel system. To do this you need to use a pressure gauge. The standard pressure for most non-tuned cars is 3 atmospheres (kgf/cm2). However, check this information in the registration certificate of your car. If the pressure is significantly lower, then the problem may lie in a faulty fuel pump or dirty injectors. If the pressure is constantly low, check the fuel pump. If at first it is normal, but drops shortly after starting the engine, check the injectors. Also pay attention to the mesh in the gas tank.
It is also worth checking the insulation of high voltage wires . It is better to do this not visually, but using a tester turned on in ohmmeter mode. wire insulation value at least 0.5 MOhm . Otherwise, the wire must be replaced.
If the Check Engine light comes on after you turn the key, and then goes off a few seconds later, this means that the system is performing a self-diagnosis and there is no cause for concern.
How to get to the service station when the Check Engine light is on
When driving to a service station, try to maintain a gentle driving regime. In particular:
- do not exceed speed more than 60 km/h;
- do not exceed engine speed more than 2500 rpm;
- turn off the air conditioner (heater), multimedia system and other currently unnecessary equipment that creates additional load on the engine;
- Avoid sudden starts and braking, drive smoothly.
You can return to normal driving only after diagnosing and eliminating the identified errors.
Replacing spark plugs and high-voltage wires
Spark plugs in a car are the main parts; they are designed to ignite the fuel mixture. With faulty spark plugs, the spark is not supplied correctly to ignite the gasoline mixture. With faulty spark plugs, it often happens that there is no spark or the timing of the supply of this spark is incorrect, and this affects the incorrect operation of the engine. If the spark plugs are not working correctly, you may feel slight jolts when accelerating the car, especially when starting from a standstill.
What are the reasons for the failure of spark plugs: -Most spark plugs in cars produced before 1996 must be changed every 25,000 - 30,000 thousand kilometers. In newer cars, these spark plugs last for more than 150,000 thousand km. But, nevertheless, these periods of planned replacement of spark plugs can be reduced due to various factors that are naturally associated with both fuel quality and driving style.
What needs to be done: -If your spark plugs have not been changed for a long time or you feel dips in the engine’s operation that are specifically related to the ignition, then you must immediately replace them with new ones without delay. Do not try to save money by untimely replacement of spark plugs, since the cost of the spark plugs itself is not as expensive as the work itself to replace them. By replacing old spark plugs with new ones, you will improve engine performance and reduce vehicle fuel consumption. Changing the spark plugs in your car yourself is quite easy. Basically, they are all easily accessible under the hood of the car. You only need a regular spark plug wrench to remove the spark plugs from the engine. It is also advisable to monitor the condition of high-voltage wires, since over time they can become unusable and allow electricity to pass through, which is transferred to the spark plugs, which can reduce the strength of the spark. Remember that regular replacement of spark plugs in accordance with the maintenance schedule for your car protects your exhaust catalyst from breakdowns, and at the same time improves the performance of the engine itself!
This article of ours was originally published in 2013, and was further updated with new information on 02/17/2020.
