Knock sensor error (codes P0325, P0326, P0327, P0328)

knock error can be caused by various reasons - a low or very high signal from it to the ICE electronic control unit (ECU), a circuit error, an outrageous output of the voltage or signal range, as well as a complete knock sensor failure (further DD), which happens very rarely . However, be that as it may, the Check Engine light is activated on the dashboard of the car, symbolizing the appearance of a breakdown, and during the operation of the internal combustion engine, there is a deterioration in dynamics, dips in speed and an increase in fuel consumption. Often, “jekichan” can also be caught after using bad fuel, but often it’s all about the contact and wiring of the DD. The error code is easily read using diagnostic scanners. For a decoding of all knock sensor errors with an indication of the causes and methods for their elimination, see below.

Knock Sensor Errors There are actually four - P0325, P0326, P0327 and P0328. However, the conditions for their formation, external signs, and elimination methods are very similar, and sometimes identical. These diagnostic codes cannot specifically report the causes of the failure, but indicate the direction of the search for a breakdown in the knock sensor circuit. Quite often, this is a bad contact in connecting the sensor to the connector or fitting its surface to the internal combustion engine, but sometimes the sensor is really out of order (it cannot be repaired, only replacement is possible). Therefore, first of all, the operation of the engine knock sensor is checked.

Error P0325

The error code p0325 is called “a breakdown in the knock sensor circuit”. In English, this sounds like: Knock Sensor 1 Circuit Malfunction. It signals to the driver that the ICE control unit is not receiving a signal from DD. Due to the fact that there were some problems in its supply or signal circuit. The cause of such an error may be very low or very high voltage coming from the sensor due to an open or poor contact in the wiring harness block.

Possible causes of the error

There are several reasons why error p0325 may occur. Among them:

• broken knock sensor wiring;
• short circuit in the DD wiring circuit;
• breakdown in the connector (chip) and / or contact DD;
• high level of interference from the ignition system;
• failure of the knock sensor;
• failure of the control unit ICE (has the English abbreviation ECM).

Conditions for fixing error code 0325

The code is set in the ECU memory on a warm internal combustion engine at a crankshaft speed of 1600-5000 rpm. if the problem does not go away within 5 sec. and more. By itself, the archive of breakdown error codes is cleared after 40 consecutive cycles without fixing the breakdown.

In order to find out what kind of problem caused the error, you need to conduct additional diagnostics.

External symptoms of a P0325 error

Outward signs of the occurrence of the mentioned error may include the following situations. However, they can also indicate other errors, so you should always perform additional diagnostics using an electronic scanner.

• the Check Engine lamp on the dashboard is activated;
• ICE control unit operates in emergency mode;
• in some cases, detonation of the internal combustion engine is possible;
• loss of ICE power is possible (the car “does not pull”, loses its dynamic characteristics, accelerates weakly);
• unstable operation of the internal combustion engine at idle.

In general, the symptoms of failure of the knock sensor or its wiring are outwardly similar to those when the car is set to late ignition (on carburetor engines).

Error diagnostic algorithm

To diagnose error p0325, an electronic OBD-II error scanner is required (for example Scan Tool Pro Black Edition). It has a number of advantages over other analogues.

32-bit chip Scan Tool Pro Black allows you to scan blocks of internal combustion engines, gearboxes, transmissions, auxiliary systems ABS, ESP in real time and save the received data, as well as make changes to parameters. Compatible with many cars. You can connect to your smartphone and laptop via wi-fi or Bluetooth. It has the greatest functionality in the most popular diagnostic applications. By reading errors and tracking sensor readings, you can determine the breakdown of any of the systems.

The error detection algorithm will be as follows:

• First you need to make sure that the operation was not false. To do this, using a scanner, you need to reset the error (if there are no others, otherwise you need to deal with them first) and make a test trip. If error p0325 occurs again, then continue on.
• It is necessary to check the operation of the knock sensor. This can be done in two ways - using a multimeter and mechanically. With a multimeter, first of all, you need to measure the voltage of the sensor when pressure is applied to it. And also check its circuit to the ECU for an open. The second, simpler, method is that at idle, just hit the internal combustion engine in close proximity to the sensor. If it is serviceable, then the engine speed will drop (the electronics will automatically change the ignition angle), which is true, such an algorithm does not work on all cars and in some cases reading the BC signal from DD works under other additional conditions).
• Check the functionality of the ECM. In rare cases, the program may crash. It is unlikely that you will be able to check it yourself, so it is better to seek help from an authorized dealer of the automaker of your car.

How to get rid of error p0325

Depending on what exactly caused the p0325 error, there are several options for solving this problem. Among them:

• cleaning contacts or replacing wiring connectors (chips);
• repair or replacement of wiring from the knock sensor to the ICE control unit;
• replacement of the knock sensor, most often it is she who is performed (this unit cannot be repaired);
• flashing or replacing the engine control unit.

By itself, the p0325 error is not critical, and the car can get to a car service or garage on its own. However, there is a risk that if a knock occurs in the internal combustion engine, the ECU will not be able to respond properly and eliminate it. And since detonation is very dangerous for the power unit, you need to get rid of the error and carry out the appropriate repair work as soon as possible after its occurrence.

Error p0326

Error with code p0326 when diagnosed, stands for "knock sensor signal out of range". In the English version of the code description - Knock Sensor 1 Circuit Range / Performance. It is very similar to error p0325 and has similar causes, symptoms, and solutions. The ECM detects knock sensor failure due to a short or open circuit by checking that the analog input signal from the sensor is within the required range. If the difference between the signal from the knock sensor and the noise level is less than the threshold value for a certain period of time, then this causes the formation of the error code p0326. this code is also registered if the value of the signal from the mentioned sensor is higher or lower than the corresponding allowable values.

Conditions for generating an error

There are three conditions under which error p0326 is stored in the ECM. Among them:

1. The amplitude of the knock sensor signal is below the acceptable threshold value.
2. The ICE electronic control unit (ECU) operates in fuel knock control mode (usually enabled by default).
3. The error is not entered into the memory of the electronic device immediately, but only on the third drive cycle, when the internal combustion engine is warmed up to operating temperature and at a CV speed above 2500 rpm.

Causes of the p0326 code

The cause of the formation of error p0326 in the ECM memory can be one or more of the following situations:

1. Bad contact
2. Rupture or short circuit in a chain of the gauge of a detonation of the car.
3. failure of the knock sensor.

Diagnosis and elimination of error code P0326

First of all, you need to make sure that the operation was not false. To do this, as described above, you need to reset (delete from memory) the error using the program code, and then make a control trip by car. If the error occurs again, you need to look for the cause of its occurrence. So, the check must be performed according to the following algorithm:

• Turn off the ignition and disconnect the wires connecting the computer and the knock sensor from one and the other device.
• Using a multimeter, you need to check the integrity of these wires (in other words, “ring” them).
• Check the quality of the electrical connection at the points of connection of the wires to the computer and the knock sensor. If necessary, clean the contacts or make mechanical repairs to the fastening of the chip.
• If the wires are intact and the electrical contact is in order, then you need to check the tightening torque in the seat of the knock sensor. In some cases (for example, if it has already been replaced and a car enthusiast screwed it “by eye”, not observing the value of the required torque), the sensor may not be enough. Then you need to find out the exact value of the moment in the reference literature for a particular car and correct the situation using a torque wrench (usually the value of the corresponding moment is about 20 ... 25 Nm for passenger cars).

The error itself is not critical, and you can operate the machine with it. However, this is risky, because in the event of fuel detonation, the sensor may report incorrect information to the computer, and the electronics will not take appropriate measures to eliminate it. Therefore, it is desirable to eliminate both the error itself from the ECM memory as soon as possible, and to remove the reasons why it arose.

Error p0327

The general interpretation of this error is called "low signal from the knock sensor” (typically, the signal value is less than 0,5 V). In English, it sounds like: Knock Sensor 1 Circuit Low Input (Bank 1 or Single Sensor). At the same time, the sensor itself may work, and in some cases it is noted that the Check Engine light on the dashboard is not activated because the “check” light only lights up when a permanent breakdown occurs after 2 drive cycles.

Conditions for generating an error

On different machines, the conditions for generating error p0327 may differ, but in most cases they have similar parameters. Let's consider this situation on the example of a popular domestic car of the Lada Priora brand. So, code P0327 is stored in the ECU memory when:

• the value of the crankshaft speed is more than 1300 rpm;
• coolant temperature over 60 degrees Celsius (warmed up internal combustion engine);
• the amplitude value of the signal from the knock sensor is below the threshold level;
• the error value is formed on the second drive cycle, and not immediately.

Be that as it may, the internal combustion engine must be warmed up, since detonation of the fuel is possible only at high temperatures.

Causes of the p0327 code

The causes of this error are similar to those described above. namely:

• poor fastening / contact DD;
• a short circuit in the wiring to ground or a breakdown in the control / power supply circuit of the knock sensor;
• incorrect installation of DD;
• failure of the fuel knock sensor;
• software failure of the electronic control unit ICE.

Accordingly, you need to check the specified equipment.

How to make a diagnosis

Checking for an error and searching for its cause should be carried out according to the following algorithm:

• Check for false positives by resetting the error. If, after recreating the conditions for its occurrence, the error does not appear, then this can be considered a “glitch” of the ICE control electronics.
• Connect a diagnostic tool with the appropriate software to the adapter connector. Start the internal combustion engine and warm it up to the operating temperature of the internal combustion engine (if the internal combustion engine is not warmed up). Raise the engine speed above 1300 rpm with the gas pedal. If the error does not appear, then this can be finished. If it does, continue checking.
• Check the sensor connector for dirt, debris, engine oil, and so on. If present, use cleaning fluids that are safe for the plastic housing of the sensor to get rid of contaminants.
• Turn off the ignition and check the integrity of the wires between the sensor and the ECU. For this, an electronic multimeter is used. However, a broken wire, in addition to error p0327, also usually causes the above errors.
• Check knock sensor. To do this, you need to dismantle it and measure its internal resistance using the same electronic multimeter, switched to the resistance measurement mode (ohmmeter). Its resistance should be approximately 5 MΩ. If it is very low, then the sensor is out of order.
• Continue checking the sensor. To do this, on the multimeter, turn on the measurement mode of direct voltage (DC) within about 200 mV. Connect the multimeter leads to the sensor leads. After that, using a wrench or a screwdriver, knock in close proximity to the sensor mounting location. In this case, the value of the output voltage from it will change. After a couple of seconds, the value will become constant. If this does not happen, the sensor is faulty and needs to be replaced. However, this test method has one drawback - sometimes the multimeter is not able to catch the slightest voltage fluctuations and a good sensor can be mistaken for a faulty one.

In addition to the verification steps relating specifically to the operation of the sensor, make sure that the error was not caused by extraneous sounds, such as vibration of the crankcase protection, knocking of hydraulic lifters, or simply the sensor was poorly screwed to the engine block.

After fixing the breakdown, do not forget to erase the error from the computer's memory.

Error p0328

Error code p0328, by definition, means that "knock sensor output voltage above threshold” (usually the threshold is 4,5 V). In the English version it is called Knock Sensor 1 Circuit High. This error is similar to the previous one, but the difference is that in this case it can be caused by a break in the signal / power wires between the knock sensor and the electronic control unit or by shorting the wiring section to the computer to “+”. Determining the cause is hampered by the fact that such an error pops up much more often not due to problems with the circuit, but due to poor fuel supply to the combustion chamber (lean mixture), which happens due to clogged nozzles, poor fuel pump operation, poor-quality gasoline or phase mismatch and installation early ignition.

External signs

Indirect signs by which it can be judged that error p0328 is occurring are similar to those described above. namely, the Check Engine light on the dashboard is activated, the car loses its dynamics, accelerates poorly. In some cases, increased fuel consumption is noted. However, the listed signs may indicate other breakdowns, so mandatory computer diagnostics are needed.

The cause must be sought by examining the symptoms, and the search itself by removing the connector for connecting the knock sensor on a running internal combustion engine. you need to measure the parameters of the indication and observe the behavior of the motor.

Causes of the p0328 code

The causes of error p0328 may be the following breakdowns:

• damage to the knock sensor connector or its significant contamination (ingress of debris, engine oil);
• the circuit of the mentioned sensor has a short circuit or open circuit;
• the knock sensor is faulty;
• there are electrical interferences in the sensor circuit (pickup);
• low pressure in the fuel line of the car (below the threshold value);
• use of fuel unsuitable for this car (with a low octane number) or its poor quality;
• error in the operation of the electronic control system ICE (failure).

also one interesting reason that drivers note is that a similar error can occur if the valves are not adjusted correctly, namely, they have a very wide gap.

Possible troubleshooting options

Depending on what causes the error p0328 was caused, the ways to eliminate it will also be different. However, the repair procedures are completely the same as those described above, so we simply list them according to the list:

• check the knock sensor, its internal resistance, as well as the value of the voltage it outputs to the computer;
• make an audit of the wires connecting the electronic unit and DD;
• to revise the chip where the sensor is connected, the quality and reliability of the contacts;
• check the torque value at the knock sensor seat, if necessary, set the desired value using a torque wrench.

As you can see, the verification procedures and the reasons why errors p0325, p0326, p0327 and p0328 appear are largely similar. Accordingly, the methods of their solution are identical.

Remember that after eliminating all the faults, it is imperative to erase the error codes from the memory of the electronic control unit. This can be done either using software tools (preferably), or simply by disconnecting the negative terminal from the battery for 10 seconds.

Additional recommendations

Finally, it is worth noting a few interesting facts that will help motorists get rid of problems with the knock sensor and specifically with the phenomenon of fuel detonation.

First, you should always take into account that there are sensors of different quality (from different manufacturers) on sale. Often, motorists noted that cheap low-quality knock sensors not only work incorrectly, but also quickly fail. Therefore, try to buy quality products.

Second, when installing a new sensor, always use the correct tightening torque. Accurate information can be found in the manual for the car or on specialized resources on the Internet. Namely, the tightening must be performed using a torque wrench. Moreover, the installation of DD must be carried out not on a bolt, but on a stud with a nut. It will not allow the sensor to loosen its fastening over time under the action of vibration. Indeed, when the fastening of a standard bolt is loosened, it or the sensor itself can vibrate in its seat and falsely give information that detonation is located.

As for checking the sensor, one of these procedures is to check its internal resistance. This can be done using a multimeter switched to resistance measurement mode (ohmmeter). It will be different for each sensor, but the approximate value will be about 5 MΩ (should not be too low or even equal to zero, since this directly indicates its failure).

As a preventive measure, you can spray the contacts with a liquid to clean them or its analogue in order to further reduce the likelihood of their oxidation (review both the contacts on the sensor itself and its connector).

Also, if the above errors occur, you should always check the condition of the knock sensor wiring. Under the influence of high temperatures over time, it can become brittle and damaged. It is sometimes noted on the forums that banal wrapping of wiring with insulating tape can solve the problem with an error. But for this it is desirable to use heat-resistant electrical tape and insulate in several layers.

Some car owners note that one or more of the above errors may occur if you fill the car with low-quality gasoline with an octane rating lower than prescribed by the internal combustion engine. Therefore, if after checking you did not find any malfunctions, just try changing the gas station. For some car enthusiasts, this has helped.

In rare cases, you can do without replacing the knock sensor. Instead, you can try to restore its performance. namely, with the help of sandpaper and / or a file, it is necessary to clean its metal surface in order to remove dirt and rust from it (if they are there). So you can increase (restore) the mechanical contact between the sensor and the cylinder block.

also one interesting observation is that the knock sensor can mistake extraneous sounds for detonation. An example is a weakened ICE protection mount, due to which the protection itself rattles on the road, and the sensor can falsely work, send a signal to the computer, which in turn increases the ignition angle, and the “knocking” continues. In this case, the errors described above may occur.

In some models of machines, such errors may appear spontaneously, and it is difficult to repeat them. Indeed, in some cars, the knock sensor only works at a certain position of the crankshaft. Therefore, even when tapping on the internal combustion engine with a hammer, it can be impossible to reproduce the error and understand the reason. This information needs to be clarified further and it is better to contact a car service for help with this.

Some modern cars have a rough road sensor that disables the knock sensor when the car is driving on rough roads and the crankshaft is slamming and producing a sound similar to fuel detonation. That is why checking the knock sensor when the internal combustion engine is running, when something heavy is hit on the engine, after which the engine speed drops, is not always correct. So it is better to check the value of the voltage it produces during the mechanical impact on the internal combustion engine.

It is better to knock not on the engine block, but on some fasteners, in order not to damage the motor housing!

Hack and predictor Aviator

As mentioned above, all four errors described are not critical, and the car can drive to a garage or car service on its own. However, this will be detrimental to the internal combustion engine if detonation of the fuel in the internal combustion engine takes place. Therefore, if such errors occur, it is still desirable to get rid of them as soon as possible and eliminate the causes that caused them. Otherwise, there is a risk of complex breakdowns, which will lead to serious, and most importantly expensive, repairs.