The check engine light came on: 7 troubles

What is a check engine?

“Check Engine” is translated from English as “Check the engine.” On different cars, on the dashboard there is either such an inscription, or simply “Check”, or an engine icon. On the Priora, it is the yellow icon that lights up, resembling an engine in shape. “Check” lights up in two cases:

Checking the functionality of the sensors. When you turn on the ignition, all the icons on the dashboard light up, indicating that there is a signal from the ECU and the system is ready to operate. After 2-3 seconds of turning on the ignition, the icon will go out.
Malfunction of the engine operating system. There are several important aspects. Firstly, the ECU does not receive data about all breakdowns: it cannot technically record any mechanical damage. Secondly, the appearance of this icon may be erroneous. But you shouldn’t trust the opinion “it’s all for nothing” - a problem with the engine can grow like a snowball and cost a pretty penny if you ignore it. Regardless of whether the “check” on the Priora is on or flashing, the problem needs to be solved.

Check light on Priora - you need to know the reasons

When you turn the ignition key of a Priora car, all electronic systems are checked and the check light comes on for a few seconds, this is normal, as it should be.
It’s bad when the check light doesn’t light up when you turn on the ignition, which means the check system isn’t working. If the checkbox on a Priora comes on and is lit when the car is started, the owner immediately falls into panic for some reason - at least in most cases. There's no need to panic, but I wouldn't recommend not paying attention. The engine has 16 valves - Priora is equipped with sensors in many components and this may indicate a breakdown. The check light is on on the dashboard of the Priora car, bottom left. Sometimes the check light comes on, you look, and it just drove through a puddle and the knock sensor got wet. The check light is on, it blinks when cold, but there is no need to panic, we need to look for the reasons. Let's make a reservation right away: there are false positives. Read the article and find out all the reasons why the check engine is triggered.

check engine on a Priora - looks like this

PRINCIPLE OF OPERATION OF CARS WITH ECM (ELECTRONIC ENGINE CONTROL SYSTEM)

Cars with conventional carburetor engines have been replaced by cars in which fuel enters the cylinders through a system of nozzles (injectors). And sparking occurs not in the distributor (distributor), but in a special ignition module. This rather complex system is controlled by a special intelligent unit. You could say it's a computer. It is he who sends signals to trigger all actuators. Therefore, the entire ECM system can be divided into three parts.

Computer (ECU).
Actuators (injectors, spark generators, etc.).
Sensors (Air, oxygen, throttle opening, crankshaft position, etc.)

PURPOSE OF THE CHECK ENGER WARNING LAMP ON PRIOR

What does the “Check” indicator light have to do with this system? The most direct. The fact is that this lamp is directly connected to the ECU (electronic control unit). This warning light comes on when the ignition is turned on. This gives a signal that the main unit is ready for operation. After starting the engine, after 2-3 seconds, the lamp goes out. This means that the motor and all devices are operating normally. And you can safely continue moving.

IF THE LIGHT IS ON

But when the warning light does not go out while the engine is running, or lights up while driving, this means that one of the computer-controlled components is not working correctly, or has generally failed. Literally, “Check Anger” means check the engine.

It is a mistaken opinion that the “Check” lights up when one sensor breaks down. You need to know that this signal can appear for a very large number of reasons! In general, if you read it correctly, from English, this signal, “Check Angier,” means “Check Engine.”

HOW TO DIAGNOSIS THE ECM

Of course, the most correct action if the “Check” signal lights up on the instrument panel is to go to a service center for diagnostics. There, through a special adapter, a desktop computer or laptop equipped with a licensed program will be connected to the Priora ECU. And they will be able to “talk” to the Priora ECU.

However, at the moment, small mobile devices have appeared in the car accessories market. Of course, they are not able to conduct a full-scale diagnosis of the Priora. But they are quite capable of reading error codes from the ECU memory. Then you just need to decipher the codes correctly. This is the case if the diagnostics provides them in digital format. In this case, you can turn to the Internet.

What is the danger of this defect?

Having discovered that the engine begins to stall, this defect must be eliminated as quickly as possible, despite the fact that signs of malfunction may disappear after re-gassing. The fact is that such a malfunction can reduce engine power, which will lead to an emergency on the road. After all, every car owner relies on the power of his engine, especially when overtaking, and since the power of the power unit will be reduced, the car simply will not have enough dynamics to complete overtaking, especially in severe frost and ice on the road. Only timely car repairs and finding out the cause of the breakdown will help to avoid a deplorable situation.

Every car owner can do this in his own garage with the simplest tools, if the work is done in stages.

If the check light comes on when starting on a cold engine

The “Check Engine” light on a Priora translated from English means checking the engine. However, on modern vehicles such as Mercedes and BMW, there is an automatic check of all systems and errors are displayed on the control panel screen, but on the Lada there is no such thing.

This icon lights up or blinks due to the following problems:

All these problems must be found and solved as quickly as possible so as not to lead to a major overhaul of the engine. Therefore, when a flashing light appears on the Priora check engine, you need to contact the service center and see experienced mechanics. Some will diagnose the problem and cure it.

In some cases, a small mobile device will help. It will help you see the problem in the garage, then you can look up the solution on the Internet.

Attention! If the car owner does not understand the design of the engine at all, then diagnosing it with his own hands will not help. It is better to leave it to experienced mechanics.

Why is the check engine blinking and the engine shaking? The car began to slow down.

Engine damaged

, check

, the engine does not pull, it jerks. I turn off the ignition. , I start it again and it’s fine.

There is no flash in the cylinder - check if there is fuel. At a normal compression level, you need to test the operation of the accounting power system. Focus on the air filter and pipe: are the clamps tightened tightly, what is the condition of the purifier box, is the air intake from outside adjusted. The tubes located on the throttle assembly are made to be firmly fixed to it. Traces of fuel leaks, visible cracks and chipped plastic are unacceptable.
The engine may stall
due to a clogged injector. For this reason, specialists categorically do not accept filling the tank with cleaners sold for injectors. In fact, no cleaning occurs - the contaminants peel off in the tank, and then the fuel line becomes clogged. There is a build-up in the small nozzle and it will get stuck.
The winding of the injector parts burned out.
Low quality fuel.
Test the spark plugs.

What's the result?

Ease of use and accessibility allow adapters for the diagnostic connector to significantly simplify the procedure for checking a car, reading and decoding ECU errors. It is also worth noting that the error can be quickly reset without having to disconnect the battery terminals, erase a critical error, etc.

Finally, we would like to add that among the commercially available adapters, there are devices that may not read errors recorded in the ABS unit and Airbag airbag modules. In other words, information on these items may not be available. For this reason, before purchasing an adapter, it is necessary to separately clarify the possibility of reading errors from the memory of the above and other ECM modules by one or another device.

Sensors

Engine friction can be caused by 2 sensors. One of them is the idle speed sensor. If he makes a mistake, the engine will stall when cold. After warming up everything returns to normal. The problem may also be caused by the crankshaft position sensor. Usually the problem with it is visible during diagnosis.

Conclusion

. There are many engine-related malfunctions. At the same time, even seemingly harmless ones can cause a bunch of other problems. Therefore, it is important to know all the reasons why the Priora 16-valve engine triples. This will help you quickly eliminate the problem, which significantly reduces engine life. It also brings closer the need for major repairs.

The check light came on on the Lada Priora 8 and 16 valves: reasons, what to do?

As a rule, the appearance of a check in a car occurs suddenly, at the most inopportune moment. Many car owners cannot immediately understand the reason for the error light and begin to panic.

Modern cars, for example, Mercedes-Benz, Audi, VW or Porshe, have automatic diagnostics that scan all systems for errors and malfunctions. After automatic diagnostics, a decoding is displayed on the dashboard, but such diagnostics will not show the very reason for the engine error.

Let's look at the reasons why the check engine light comes on and how to eliminate it using the example of a Lada Priora car.

Check engine error on Priora

The reasons why the check light on the Priora came on could be:

incorrect composition of the combustible mixture;
problems with spark plugs;
problems with engine speed readings and much more.

The engine is shaking and the “check” is blinking: possible causes of the malfunction

As you know, the injection engine has replaced the carburetor engine mainly due to its efficiency, as well as the reduced amount of harmful emissions into the atmosphere. This became possible as a result of flexible adjustment of the operation of the internal combustion engine using the electronic control system of the ECM.

Note that the indicated “check” lights up for various reasons. In this article we will talk about why the check light blinks, the engine stalls, or the power unit is unstable in different modes, and such operation is accompanied by a lit internal combustion engine fault indicator.

How to diagnose the ECM

As I already said, when errors like check engine appear, the Priora car owner has two options: solve it yourself or you can contact a car repair shop. The car owner can use a portable mobile device to read the fault codes from the electronic control unit that contributed to the appearance of the check on the Priora vehicle.

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It is necessary to correctly understand the cause of Check Engine on Priora and decipher it. Some error numbers can be found in the operating book for the “heart” of the vehicle. The rest can be found on the Internet.

For example, if the check engine light is on, this means that the following causes of engine malfunction have arisen:

broken track sensor;
adsorber is faulty;
The mass air flow detection device does not work.

Fault codes will tell you that one of the systems or components has failed and needs to be replaced.

How to dismantle and install the Priora dashboard

To dismantle the module, you will need to prepare two screwdrivers – a Phillips and a flathead one. A complete replacement of the Priora tidy looks like this.

Disconnect the wires from the battery.
Pull the steering column all the way down and remove the steering wheel from the pin.
You will also need to remove the cover covering the fuse box.
Unscrew the 4 bolts holding the instrument panel and remove it.
Loosen the two mounting bolts of the trim panel and remove it.
Disconnect the wiring harnesses from the contact groups and completely remove the board from the machine.

Installation is performed in reverse order.

If the check light comes on when starting on a cold engine

If, when you turn on the ignition, there is no characteristic sound of fuel pumping, and the engine icon lights up on the panel, then most likely the relay supplying power to the fuel pump is faulty.

The exact location of this device depends on the specific vehicle model and may be in the immediate vicinity of the fuel injection control unit or near the fuse box. The reasons why the relay does not operate can be either a malfunction of the device itself or a failure of the fuse protecting it.

Why does the “check” light up: the most common and common malfunctions

So, we figured out the general scheme. Now let's look at what problems lead to the check light coming on and the engine stalling. Often a p0300 error occurs, which indicates that a misfire (misfire) is occurring. There are several reasons for these omissions, and to determine them it is necessary to carry out a step-by-step diagnosis, taking into account certain individual symptoms.

You should start by checking the ignition system. The most common cause of tripping is the failure of spark plugs and armored wires. Candles can wear out their service life, break down, or become heavily contaminated. Armored wires suffer from insulation damage and breakdowns. One way or another, the result is either no spark at all, or there is a spark, but it’s weak.

If everything is in order with the spark plugs and wires, you should pay attention to the ignition module or ignition coils, which may be shorting. In this case, it is better to entrust the check to experienced specialists, since unprofessional actions lead to the fact that you can burn the switch or damage other important elements.

Having dealt with the ignition system, it is necessary to check the power system. As a rule, incorrect operation of injection nozzles or malfunctions in their operation lead to engine tripping. At the same time, the check will light up or flash.

The best option would be to check the injectors on a special stand. Such diagnostics allows you to determine the need to clean, repair or replace injectors. At the same time, specialists check the power supply to the injectors, the condition of the injector O-rings, etc.

As for compression, a burnt-out valve often leads to an unexpected decrease in the indicator. If the valve burns out, the engine starts to run rough. In this case, tripling is constant and occurs in all modes of engine operation. Engine thrust drops significantly, and significant excess fuel consumption is observed.

Please note that in this case you cannot drive the car, as there is a high risk of damaging the catalyst and oxygen sensor (lybda probe). To confirm the diagnosis, you need to measure the compression, and to solve the problem itself, you need to remove the cylinder head, troubleshoot the head and change the valve.

Priora: why the check is blinking or on - the main reasons

The diagnostic connector will help you “talk” to the electronic control unit and find out why the check light is on. Well, before you start diagnosing, check out the list of the most common Priora “errors”:

The reasons for the “Check” fire on a Priora (16 valves), as we see from the list, can be serious. There is no need to panic: when the “Check” light comes on, you need to immediately reach for the diagnostic connector. It’s funny, but earlier diagnostics were carried out in the service with special software, but today any error code can be displayed on your smartphone, deciphering it using a mobile reading device.

There is another reason for engine malfunction - low-quality gasoline.

If this causes the spark plugs to flood, you will see the “check” blinking. Low-quality gasoline can be sold at any gas station; experienced car enthusiasts advise carrying a couple of candles with them. Sometimes the “Check” light comes on due to gasoline and the engine stalls. If he continues to work intermittently, things will be bad.

“Check” should light up when the ignition is turned on. A malfunction is also considered to be the case when the check light does not light up when the ignition is turned on, that is, the ECU does not send a system check report stating that “the system is ready for operation” - there is a problem in the wiring. You need to get rid of the chek icon not so as to “hide all the problems”, but so that the process of processing the fuel mixture occurs in order. Otherwise, you will have to seriously repair the car.

On the Priora, the engine starts to stall and the check light comes on

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I would be glad to have any thoughts on this matter, as at 60 thousand mileage some problems only appear.

The check is flashing - it means misfire. This is already understandable - it’s a troit. So diagnostics will not give anything.

How will it determine which cylinder (coil)?

Is there something to replace the voltage wires with as a test?

But he doesn't have them. Neither central. no other. The coil is weird (already answered). The problem is identifying it.

Causes and troubleshooting when the check engine light comes on on a Priora

If the check light is on on a Priora, there are two ways to solve this problem. This means resetting the error codes and driving on as if nothing had happened. However, such negligence can lead to the engine soon failing. And the next time the check on the Priora is on, the VAZ will simply stop.

Attention! A reset is only done if the diagnostics find no problems. For example, wiring faults. The car owner resets the check engine and replaces the wires.

Another option is to find and treat the problem that has arisen. Incorrect operation of the valves can lead to the appearance of a check on the Priora. Since exhaust gas systems may not work properly. This will lead to frequent detonation of the engine and cause it to fail.

Triggering of the check lamp after washing the car

If the check light on a Priora comes on after washing, then the reason most likely lies in a shorted wiring. You should dry the Priora engine thoroughly and turn on the ignition again. If the problem does not go away, then try resetting the ECU error.

Start the engine and see if the light goes out or not. If it doesn’t disappear, then it’s not the wash. Most likely there is a problem with the oxygen sensor.

Oxygen sensor

Many inexperienced car owners ask: “Why does Priora’s fuel consumption increase?” This is due to the oxygen sensor. This is often why the check engine lights up and indicates that the sensor is broken and needs to be replaced.

It can be detected by the vehicle's falling power. And the sensors break down due to the large amount of used oil that remains on the engine parts after several years of operation. The tightness is broken due to the deterioration of the plastic, since in domestic regions cold winters and hot summers destroy the plastic on the sensors.

A broken sensor sends signals to the ECU indicating a malfunction. The check light on the Priora comes on. It is necessary to check the condition of all sensors. There are only four of them. And replace the faulty one.

The device can be found in two places: 1. in the exhaust manifold, 2. after the catalyst.

Faulty spark plugs and more

The car makes sudden jolts when driving. The check engine light comes on in a Priora. This all indicates that the spark plugs are faulty. The spark is so delayed that the mixture is ignited at the wrong time. Therefore, only an experienced mechanic can figure this out. It is not recommended to climb into the engine yourself.

The engine starts to stall. The spark plugs are also faulty. They have a service life. Typically, spark plugs last no more than 50 thousand kilometers. After a similar amount of mileage, it is recommended to replace them.

If the check light was on on a Priora only for this reason, then after changing the spark plugs, the lamp will stop flashing or burning. If you change this equipment yourself, you will need a spark plug wrench.

Other

A leaky fuel system on a Priora 16 can also cause the check engine light to light up. To avoid this mistake, the car owner will need to check whether the fuel tank cap is tightly closed. If not, then unscrew and re-tighten the cap.

If it doesn’t help, it means that the rubber gasket is leaking. We remove the old one and install the new one.

Problem with the gas pump and fuel filter. They can also be the culprit for the check engine light being on. To correct this situation, change the filter device and the pump that pumps fuel.

Fuel with a low octane number in Russia is a leading problem among car owners. Bad fuel clogs injectors, destroys spark plugs and other components of the Priora engine. You just need to replace the fuel with a higher quality one, and all the problems with the engine check on the Priora will disappear.

Another problem if the check light on the Priora is low is the lubricant level. You need to add oil, and the light will go out on its own.

How to connect the Volga signal

Standard sound signals of LADA cars consume no more than 5A, and Volga horns consume 7A each. In this regard, to connect them it is necessary to use a 4-pin relay. The Volga signal connection diagram is universal for all cars:

Before starting work, it is recommended to disconnect the negative terminal from the battery. All wires are laid in corrugation. We place the relay in a place protected from moisture and dirt. The whole process is also shown in the video:

About the guarantee. If you independently modify the car in terms of electrical components, there is a possibility of refusing warranty service for the car. Therefore, the installation of signals from Volga should be carried out at a service center, where after connection they will be ready to provide a document confirming the quality of work. You can also contact an authorized dealer for such modifications.

Are you satisfied with the operation of the standard sound signal on the LADA model? Are you ready to install a Volga horn? Let us remind you that we previously looked at other methods that can make operating a car more comfortable. For example, installing a gas tank cap bracket or how to make a flip-flop ignition key.

How to check engine errors and erase the error in the ECU memory

To carry out engine diagnostics and read error codes, as well as to reset them, many drivers prefer to go to a service station where there is a scanner. Service station specialists, at the owner’s request, can issue a printout that will display the error codes recorded in the control unit’s memory. Note that this procedure is optimal in the case when the check is constantly on. If the error is “floating” (the check periodically lights up and goes out), then a visit to the service may not yield anything.

In such a situation, you can buy a scanner for personal use, but its cost and the need to study the features of the software make this method impractical, especially when it comes to diagnosing only one car. Let us add that the scanner is used in parallel with a laptop or personal computer, which creates additional inconvenience.

All kinds of third-party BCs (on-board computers) also rightly belong to similar ones in terms of ease of use, cost and feasibility of purchase. The solution is capable of reading and deciphering error codes and displaying additional information about the parameters and operating modes of the internal combustion engine. At the same time, the BCs require proper connection and separate installation in the cabin.

Among the main advantages of such adapters is that the device is a small, compact “box” that is inserted into the diagnostic socket of your car. This means that the need to connect, lay wires, place the device itself in the cabin, use a PC and perform other additional actions is completely absent.

The adapter in the connector remains almost invisible and connects to a tablet or smartphone “over the air” thanks to bluetooth/wi-fi technology. This is especially convenient when the engine error lights up periodically. In other words, you can drive with the adapter in the connector as long as you like, and at the moment the check light comes on, immediately read the fault code. You only need to secure your smartphone or tablet to a stand or holder to be able to monitor the readings on the screen while driving.

As for the software, it may be supplied with the adapter. The necessary programs are also available in the Play Market for Android and similar solutions for devices on other operating systems. The software must be installed on a smartphone/tablet. Note that among the various available solutions, the Torque program is very popular (a free version of this application is available in the Market for Android). The program allows you to flexibly customize the interface, has the ability to not only read, but also decipher errors, and has the ability to reset engine errors.

Oxygen sensor

The "check engine" warning sign indicates a malfunction of the engine. First of all, you should check the operation of the oxygen sensor. It relates to the exhaust gas production system, so it shows the amount of oxygen that has not been burned in the combustion chamber of the engine. The device provides control of gasoline consumption on a Lada Priora car.

If the sensor is broken, the vehicle's computer control system does not receive the necessary data, which can cause fuel consumption to increase and engine power to decrease. There are up to 4 oxygen sensors depending on the car model. At home, you can use a computer error scanner, or you can contact a service center.

Why does the oxygen sensor break down? The older the car gets, the larger the layer of used engine oil on the parts, which reduces the correct operation of the sensors. If you do not change and check the condition of the oxygen sensors in the Lada Priora, the catalyst will break, which may burst and lead to serious repairs. New catalysts are expensive due to the presence of valuable metals in them, so it is better to focus on preventing the problem. If the check engine light comes on, you need to look into the sensors and determine the reasons.

When the seal is broken

When the check engine light comes on, you need to check the tightness of the fuel system; this is the reason why the light may be on. Don’t immediately suspect serious damage; start with small but important details. If there is a leak in the fuel system, air escapes somewhere in the fuel tank filler cap. This increases the overall fuel consumption, a malfunction occurs, so the system reports an error.

Check the engine operation of the Priora by ear. If the “check engine light” is on, the car is still running at normal power, there are no extraneous sounds from the running engine, no knocks, hums or squeaks, then the problem is the tightness of the fuel tank. From a technical point of view, it may be that the lid is not tightened enough or there is a crack in it. Correct what you can do with your own hands and see if the light on the Priora continues to light. Perhaps the problem will be solved after tightening the cover or replacing it.

Another problem that leads to a burning “check” is the exhaust gas catalyst on the Lada Priora. It serves to clean exhaust gases. Without a properly functioning part of this type, not only the driver suffers, but also the environment, as the composition of the exhaust gases deteriorates. The catalyst converts carbon monoxide and has an important function. This is also dangerous for the driver, and it is undesirable to drive with a malfunction of this kind. If the problem is in the catalyst, then the power will decrease by 2 times. In this case, a warning message will light up on the dashboard. Press the gas pedal and analyze the dynamics of acceleration.

What to do?

The first sign that it is necessary to diagnose the car engine is the long burning of the check sensor. Considering that the blinking of this assistant may indicate serious problems, you should not ignore this procedure. However, for various reasons, vehicle owners cannot send their cars for inspection or are confident that the engine’s operation is not impaired.

Some drivers advise disconnecting the battery terminals for a few minutes to reset the sensor error. If reconnection does not work and the lamp continues to light, you should contact diagnostics. Do not forget about timely replacement of spark plugs, since the appearance of carbon deposits is the second reason for the continuous burning of the engine operation sensor.

It is worth noting that not only Priora owners complain about this problem. Many drivers, both domestic models and foreign cars, record the activation of the check due to abnormal weather conditions or bad gasoline. At a service station, engine diagnostics will cost about a thousand rubles. Considering that engine overhauls are much more expensive, it makes sense to take the time to check the power unit.

Of course, if after drying the car, replacing oil, spark plugs, gasoline, wires or other surface faults, the indicator does not blink, it means that the problem has been resolved and you can drive without visiting a service station. The main reasons why the check light on a Priora is on and the engine is running normally may indicate minor problems in the ignition elements, fuel or battery. This problem can also occur during severe frosts and after heavy rainfall.

My husband returned from work in the evening, and there is an opportunity to write you an answer to why the check light is on on the Priora. I will try to indicate, if not all, then at least the most common reasons. Another thing is that I don’t understand at all how you can identify a rational grain from all this information. But that, in essence, is no longer my business. And so, let's go.

The check light is on if the engine runs intermittently. Both barely noticeable and significant.

One of the ignition coils is faulty. On Priors this is one of the most common reasons.
The power circuit of one of the ignition coils is faulty. For example, somewhere the wiring is damaged. Sometimes the cable rubs against various nearby equipment. For example, about the cooling system hoses.
The control circuit of any of the ignition coils is faulty. The same thing, we look at the wires, or alternatively, one of the transistors in the electronic unit that controls the coils has died.
One of the spark plug caps is faulty. It is difficult to see, because To do this you have to remove the coil. It is calculated empirically by moving it to another cylinder. This malfunction can be judged with 100% probability if, when removing the coil from the channel, its cap is covered with oil. Oil ingress causes breakdown of both the cap and the coil itself subsequently.
One of the spark plugs is faulty. When unscrewing the spark plugs, they will be wet, because... There was no combustion of fuel in this cylinder. Possible breakdown of the insulator. In this case, there will be a thin brown path on it. It looks something like this:

The engine runs steadily, but the car's dynamics are mediocre.

The very first reason is fuel pressure. The mixture is either lean if it is small, or rich if it is large. For example, the pressure is low. The reason for this may be a clogged fuel filter, a crumpled fuel tube under the bottom when you accidentally ran over something and hit the bottom, a worn fuel pump, low supply voltage to the fuel pump due to a faulty pump relay, or poor contact in the wire connections.
The pressure is high. In this case, the fuel pressure regulator is clearly to blame.
There is a danger of loosening the timing belt tension. In this case, the timing phases will be slightly off, which will lead to jumps in the ignition angle, because The ECU will strive to compensate for the phase loss. The malfunction is dangerous, because if the timing belt breaks or jumps off, engine repair is terrible and expensive.
The mass air flow sensor has exhausted its service life and is giving incorrect readings. In this regard, the mixture will be incorrect, often in the direction of overconsumption, but the check will light up only if the mass air flow sensor completely fails.
Incorrect operation of the crankshaft sensor. There is a dogma that it either works or it doesn't. But not everything is so flat and parallel. Often the sensor continues to work, but gives an unreliable signal, due to which the ignition actually goes beyond normal limits, and the overall engine operating schedule is also out of range. The check light comes on because the motor operating parameters do not fit into the definition area of the program recorded in the memory of the electronic unit.
The catalyst is clogged. A rare malfunction, however, the car's dynamics will be terrible, and the check will light up, since the readings between the lambda1 and lambda2 sensors will go beyond the detection range.