P0300 is a faulty ignition order. Misfires: Causes and Troubleshooting High RPM Misfires

The Check Engine lamp lights up on the car's instrument panel with various errors and requires immediate reading of information from the electronic control unit using a diagnostic scanner that will help you sort out the problem. Error P0300, which can be detected during the test, indicates the presence (violation of the ignition order). If the diagnostic scanner is not localized into Russian, it will display the message "Random cylinder misfire detection system", which can literally be translated as "Random multiple cylinder misfires".

The P0300 code can vary on some vehicles, ranging from P0300 to P0312. This is due to the fact that if the car's electronic control unit is able to independently determine in which cylinder the misfire occurs, it indicates this to the driver. That is, the last digit in the combination "P030x" changes. If the engine has 12 cylinders, then the value will change up to P0312, and if 6, then the maximum possible error is P0306, which will report problems in the sixth cylinder.

Table of contents:

Please note: Most often, error P0300 is encountered on VAZ Priora, Kia, Opel, Chevrolet, Ford and Nissan cars. But it is possible to detect it on machines of other brands.

When the P0300 code is diagnosed

In order for the P0300 error to be determined and recorded in the ECU memory, the system must determine the presence of a misfire in several cylinders at once. If the engine is idling, then error P0300 will be stored in the memory 210 seconds after it is started. If the revolutions are above 2000 per minute, then it will take less time to write the error to memory - about 1 minute. For an error to be detected by the system, more than 3.25% of flashes per 1000 crankshaft revolutions must be missed.

How does the P0300 code affect engine performance?

The driver, before diagnosing the behavior of the car, can easily determine that the diagnostic scanner will indicate an error P0300, P0301 or another one from the series. Symptoms of engine operation with the error in question are characteristic of a misfire problem:

• The engine shakes strongly at low speeds and at idle;
• When accelerating, the car "throws and jerks";
• Fuel consumption is greatly increased;
• There may be problems with starting the engine;
• The traction is reduced.

If these symptoms occur and the Check Engine light is on on the instrument panel, there is no doubt that the diagnostic scanner will show one of the errors of the P0300 family.

Causes of P0300 Series Errors

To accurately determine the cause of the P0300 error, you will need to diagnose the main systems that may fail. A misfire in a cylinder is possible in a situation where there is nothing to burn (that is, fuel is not supplied or is of poor quality) or it is not possible to ignite. Accordingly, the main causes of the P0300 error are as follows:

Important: If the diagnostic scanner has detected an error P0301, P0302, P0303, P0304 or another one that indicates problems in a particular cylinder, you should look for the cause of the error in the ignition system.

Algorithm for checking elements to eliminate error P0300

Since there are many possible causes for the P0300 error, a specific troubleshooting algorithm must be followed. Here is a sequence of actions for the fastest detection of the cause of misfiring:

The above are the main steps that most often help to find the cause of the P0300 code. When checking the above elements, pay attention to their condition - the presence of soot, traces of mechanical damage, and so on.

The car lost power, the engine began to work intermittently, and the car hardly enters the climb in second gear. And you are surprised to find that the on-board computer gives an error type P - misfire in the cylinder.

What can cause a misfire in a cylinder

The classification of misfire errors is as follows:

• Р0301 - misfires in 1 cylinder;
• P0302 - misfires in cylinder 2;
• P0303 - misfires in cylinder 3;
• P0304 - misfires in cylinder 4, etc.

In this case, there are two answers: go to a car service, where specialists will help you determine the cause of the misfire, or try to find and eliminate this cause yourself.

Let's start with what is a misfire? This is a phenomenon in the engine, when one of the cylinders accelerates more slowly than the others, which violates the process of the duty cycle of the cycle. The consequences of a misfire, such as worsening exhaust or increased fuel consumption, are of little interest to us. What worries me most is that the car practically does not drive, but “twitches”.

Misfire in one cylinder is tantamount to riding a horse without one leg. Therefore, in order to quickly eliminate this problem, you need to know exactly or know in which direction to look for the cause.

And now to the causes of misfires. In fact, there are a lot of them, and we will list the most typical ones.

• The quality of the air-fuel mixture. As a result of low-quality fuel - nozzles are clogged. In this case, the elimination of the root cause is only in the replacement of the operator - refueling, or the transition to high-octane gasoline. In addition, a lean mixture can occur due to malfunctions: a fuel pump, a pressure regulator, or a clogged filter.
• Candles. They may be pierced. With a small or large gap. Yes, just poor quality.
• High voltage wires. Either with mechanical damage, or with high resistance.
• The ignition modules or coils are out of order.
• Uneven or leads to an insufficient degree of compression of the air-fuel mixture.
• Gas distribution mechanism. Cylinder misfire occurs due to incorrect (failure of wear adjustment) adjustment of timing gaps or leaks in hydraulic lifters.
• Malfunction of one of the cylinders. For example, due to a decrease, etc.

The reality is that when we misfire in the cylinders, we instinctively reach out to check the entire electrical circuit of the car, starting with the candles. But in the end, it may turn out that the real reason for the misfires in the cylinders occurred. There were faulty valves.

How to find the cause of a misfire in a cylinder

For those owners whose cars are equipped with "electronic brains", the task is slightly simplified with the use of autotesters. These clever girls immediately show us error codes, for example, misfires in cylinder 3 or misfires in cylinder 1.

Moreover, the scanner will also reveal the direction of the search for the cause. The scanner showed code P0204, and we think it's an injector malfunction. And code P0300 indicates random misfires in all cylinders. And we understand that there is a deterioration in the composition of the air-fuel mixture. So you need to look for the cause of high air leakage from the recirculation valve or low pressure due to a weak pump.

If a misfire occurs in a car without an electronic assistant, then the search for causes occurs in old-fashioned, proven ways. We start with the electrical equipment under the hood: BB wires, spark plugs, then measuring the compression in the cylinders, the state of the fuel pump.

Already at the last stage, if the misfire in the cylinder continues, we proceed to the engine. Removing the valve cover will help diagnose the condition of the rings and valve guides.

By and large, it is not immediately possible to determine the exact cause of misfiring. There are cases when the spark plugs give out a powerful spark, the phases of the gas distribution mechanism are within the normal range, the valve adjustment is normal, the compression in the cylinders does not deviate, the pressure in the fuel system is normal. In such cases, a possible cause of gaps in the failure of the electrical circuit of the injectors. For example, when starting a cold engine, tripping is observed, after reaching the operating temperature, everything stops. The opposite situation is when misfires are observed after the engine has warmed up.
The phenomenon is actually not so rare. It is enough to close the wiring at any nozzle and the whole system starts to work unstably, and misfires are observed in different operating modes of the power plant.
This can also be observed in the event of a malfunction of the sensors of the engine control unit. Spark plugs, or rather their malfunctions, are considered an obvious cause of misfires. But when checking, there may be a situation when the spark is powerful in the open air, but directly during the operation of the internal combustion engine it disappears, the operating conditions with increased pressure in the cylinders are to blame. Therefore, it is necessary to test spark plugs using special equipment that creates close to real working conditions inside the motor.

One of the most annoying problems in the operation of an internal combustion engine is misfiring. This is the moment when one of all cylinders does not work due to a malfunction in the ignition system. There is an opinion that it is incredibly difficult to determine the causes of this problem, but misfires must be fixed. At the moment of misfiring the fuel, one cylinder fails, which significantly affects the engine power - 25% of the potential of the power unit is lost. The remaining three cylinders (if we are talking about a four-cylinder engine) are forced to work for themselves and for that guy, so fuel consumption increases markedly. In addition, a misfire unit does not start well, trembles at idle and stalls under excessive loads. These are the unpleasant consequences of a misfire.

It is worth noting that the ignition can be skipped both constantly and at certain intervals, or even randomly. If there is a constant misfire, one cylinder simply refuses to work. If there is a chaotic operation of the fuel ignition system, the cylinder may either turn on or skip its turn again. This causes very unpleasant fluctuations in speed, serious jerks when the cylinder is suddenly connected. Also, the engine may stall when the cylinder refuses to work during load. It is necessary to deal with this problem and not let it take its course.

Constant misfire in one cylinder - we study and fix the problem

It is worth considering three options for the causes of a misfire in a constant mode. The first option is the lack of a spark, which can also be caused by a number of factors. The second feature of the problem is poor compression in the cylinder. This usually happens after repair work has been completed or at a time when the engine needs to be overhauled.

You can also consider the third option for the absence of fuel ignition - the low quality of the fuel mixture itself. In this case, it is worth changing the gas station and taking obviously good gasoline or diesel, pouring good fuel into the tank and driving a few kilometers. However, with poor fuel, the engine may not start at all, but a misfire is most often worth diagnosing from such nodes:

• spark plugs - a faulty spark plug is the most common problem of poor fuel ignition;
• punched high-voltage wires can also become a certain cause of such an unpleasant problem in your car;
• problems in the electronic ignition control or in the mechanical system (Hall sensor);
• depressurization of one of the cylinders, a decrease in compression and the absence of fuel ignition for this reason;
• too much cylinder wear due to uneven loads or simply a lot of engine wear;
• ignition modules in each car have their own design and differ in many ways, they are also worth checking;
• it is necessary to adjust the ignition at the service in order to understand for sure that this factor does not cause a problem;
• sometimes the reasons can lie deeper and go into the diagnostic field of an exclusively professional service.

Despite the wide range of possible malfunctions, you can check almost all the popular factors for the failure of the ignition system in your own garage. You do not need to use the services of a professional for this, unless you own an incredibly modern Japanese transport, in which even opening the hood on your own is not so easy.

If the problem was not detected on your own, you will have to contact the service center and pay for professional diagnostics. In this case, you will be able to detect and fix the problem quickly enough, as well as get a guarantee from specialists that this situation will not happen again in the near future. True, the services are also different, and not every company will help you to qualitatively eliminate problems with the car.

Temporary or interval shutdown of ignition on one cylinder

The problem of constant ignition failure is fraught with the fact that one cylinder from the general set in the car does not work. In this case, the engine shakes, it is very noticeable, power is lost and fuel consumption increases. But if the failures in the ignition are not permanent, but temporary, the problem can be perceived a little differently and interpreted at the service as a malfunction of another node.

If, while driving, you feel a periodic sharp decrease in power and an inexplicable increase, most likely we are talking about a temporary shutdown of one of the cylinders. Such a possibility exists for all the reasons listed above, but not with the final failure of any node, but with its initial failure. In this case, the symptoms of trouble with the car will be as follows:

• poor engine start and operation of three cylinders on a cold car, connection of the fourth cylinder on a hot engine;
• temporary shutdown of one cylinder with a characteristic decrease in speed and loss of power;
• very high fuel consumption and deterioration of the engine oil due to the constant ingress of gasoline into it;
• decrease in the reliability of the engine, the unit may stall for no particular reason in any conditions;
• a special manifestation of malfunctions in the cold season or at high loads on the power unit;
• reduced traction and increased engine wear due to the need for constant work under load;
• fluctuating idle speed, serious jerks during smooth movement in urban mode.

As soon as such troubles occur with your car, you need to go to the service station and diagnose the ignition system. A temporary failure of one of the cylinders most often becomes a harbinger of high costs for an engine overhaul. That is why many owners in this case prefer to put the car in order as far as possible and sell the vehicle to another owner.

If you want to rectify the situation and repair your car, be prepared for unforeseen high service costs. However, in the worst case scenario, you can buy an assembled engine for disassembly without spending too much money on this process. In this case, you can upgrade the potential of the power unit of your car and extend the life of the car for a few more years. The operation of the engine during misfires looks something like the following video:

Summing up

Misfiring can be both an innocuous indicator of a failed spark plug, and a serious demonstration of the need for professional intervention in the powertrain system. With the help of professional diagnostics, you can find out the source of the problem and get more information on how to solve this problem. Despite the many difficulties in the process of finding an ignition problem, often this problem can be solved independently without any problems.

But if we are talking about increased wear of the power unit and poor compression in the engine, you will have to spend money on repairs by performing a major restoration of the most expensive unit in your car. It is especially problematic to find and fix an ignition problem in modern German or Japanese cars. These are machines that contain advanced technology and will actually be a difficult object to carry out repair work without special skills and special equipment. Have you ever had to fix ignition problems yourself?

Cadillac Escalade P0011 and how to deal with it

The problem of code P0011 is faced mainly by owners of cars in 2007, but I also met it in 2008. It usually starts with the anti-skid system lamp on, then the check engine lights up, reporting a mismatch between the actual position of the camshaft position and the set one. The gearbox starts to work very hard. The usual way, based on the diagnostic data, directs repairmen to first change the “stretched” chain and tensioners. Next, they change the control valve of the variable valve timing system, then they try to change the oils to thicker, more liquid ones, they changed the camshaft, liners, and in the end they ended up replacing the engine. All these steps are absolutely correct and in each element from the one I described there is a possible problem that causes this malfunction, because. this phase change system operates on the pressure of the engine oil system. However the sore point is the camshaft bed, due to the wear of which, oil pressure leaks. For this reason, the camshaft does not turn to the angle set by the computer, this is fixed by the computer, checks are lit, the box enters a hard mode of operation, and the anti-skid system is also turned off. At the beginning of the disease, only the described symptoms occur, at first rarely, then more often. In the second phase of the disease, after stopping the engine, it cannot be started again until it cools down.

Treatment. There are two ways. The first is the replacement of the cylinder block, because the camshaft is one and installed in the heads, but in the collapse of the block. The second is software reconfiguration of the system. The disadvantage of the second method is that this system gives some fuel savings in quiet cruise driving modes and turning it off will slightly increase fuel consumption only in these modes. The owner himself decides which of the repairs to choose, but so far I have not met people who, knowing about the second method, chose the first one, especially since the solution to the problem is included in the cost of my regular Engine-Box firmware.

Misfiring at high rpm

I. As a rule, they occur when driving for a long time at high speed. If you have such a situation: the “Engine Malfunction” lamp suddenly flashed (in addition to this, or separately, extraneous sounds from the engine side can be heard), then first of all, reset throttle, reduce speed and rpm below 3000 and move on without exceeding them. The nature of the knock can be different - detonation or mechanical knock.

Acause - misfiring, detonation due to:

1. low-quality gasoline;
2. faulty candles, coils, high-voltage wires;
3. insufficient performance of the fuel pump at high speeds;
4. incorrect readings of the MAF sensor (including due to contamination);
5. valve sticking.

Bcause (there is a metallic knock) due to:

1. fuzzy closing, “hanging” of valves due to weakness or fatigue of valve springs, aggravated by soot on the valve stems, which prevents them from moving freely. Carbon deposits on the valves are more present on vehicles with LPG, because gas, unlike gasoline, is not able to wash off carbon deposits on the intake valves.

In most cases, during diagnostics, you will be looking for a problem only according to paragraphs 1 and 2, maximum paragraph 3, because. quite a few people know the causes thoroughly and have the time, opportunity, knowledge and desire to find the cause. Moreover, even original scanners, or rather their software, are inconvenient in troubleshooting. Therefore, I am writing this information for those who are left alone with the problem and want to understand the reason.

The first 3 points are solved by replacing faulty elements. Point 4 - possibly by cleaning the sensor (I recommend using a special liquid moth spray). Point 5 is solved by replacing the valve springs and cleaning the valve stems. I recommend immediately changing the springs not to stock, but to tuning, reinforced ones. Perhaps the solution to clause 5 is without replacing the springs, by software reconfiguring the system for changing the valve timing. In this case, the engine power at high speeds will be slightly reduced. But here the choice is up to the owner how to proceed.

Advice: If you have not even encountered the problems described above, but are a fan of active driving, then I recommend that you initially, immediately, replace the stock ones with reinforced tuning springs. Thus, get good mixture formation and power at high speeds and save yourself from more expensive repairs.

II. If some time after refueling you begin to hear knocking knocks in the engine, ideally drain low-quality gasoline, which in practice is inconvenient and difficult to do, therefore, do not give the engine loads and speeds, as soon as there is a possibility of new refueling and space in the tank - top it up up to full 98 m gasoline. The detonations will stop.

Misfires at idle and medium loads (diagnosis yields DTC P0300-P0308)

V8 engines installed on Tahoe, Escalade, H2, etc. have the same timing (valve drive) design. In the practice of repairmen and diagnosticians, there are periodically cases of misfires at idle, expressed in unstable engine operation and ignition of the CHECK ENGINE lamp. Diagnostics gives trouble codes P0301-0308 depending on the cylinder in which there are failures. After carrying out all the diagnostic procedures for this case (1- Serviceability of the ignition system 2- Serviceability of the fuel supply through the injectors 3- Compression, Tightness of the combustion chamber 4- Serviceability of the control unit according to the control signals of the ignition coils and injectors), the brain comes to a standstill - everything is in order, and the cylinder practically does not work. I won't delay answering. The reason is the hydraulic compensators of the valve drive. Their incorrect operation, due to biting and wedging, leads to improper filling of the cylinders with a fuel-air mixture and the impossibility of igniting it from a spark. Problems are more common when using low-quality oil and due to long oil change intervals (see also section About oil)

From rarer cases. The misfires were due to a poorly installed emergency alarm when they were introduced to the ignition coil circuits

Tahoe 2013-14. Fault code (error) P015A ,B,C,D

Typical for this year of release. Contact

HBO and cylinder deactivation system DoD

- Change the spark plugs no more than after 50 thousand km. mileage, regardless of their external condition. Do not allow an abundance of dirt and water on high-voltage wires, coils and spark plugs.

- Clean the air flow sensor every 50 thousand km

Don't Use Genuine GM Engine Oil

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