Method for determining the malfunction of the oil pressure sensor. Why do you need an oil pressure sensor in a car

normal operation of any automobile engine is impossible without many regulators. One of these is the sensor. oil pressure, designed to indicate the pressure level of the working fluid in the oil system. You can find out about the types, principle of operation, diagnostic options, what to do if DDM flows and why this happens in this article.

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Overview of DDM

An oil pressure gauge is an essential element of any modern engine. To begin with, we propose to understand what types exist, as well as what is the principle of operation of the device.

Kinds

Today, automobile DDM can be of two types:

1. Electronic oil pressure gauge, which is also often called an emergency. This device can function in several modes - either the "yes" or "no" mode. Essentially, the sensor emergency pressure oil does not allow you to give accurate indicators of the functioning of the system. Such a device can only inform the driver that the pressure of the working fluid has completely disappeared in the power unit. The device that is in the motor warns the motorist thanks to the control lamp - if it lights up on the instrument panel, then this element of the circuit must be changed or the system's performance must be checked.
2. Mechanical oil pressure gauge. Such a device, unlike an electronic counterpart, when connected, allows you to accurately determine the level of fluid pressure. The driver is alerted using a control lamp, as well as a scale that is on dashboard.

Depending on the vehicle, two types of regulators can be used at once. Thanks to this, the driver has the ability to control the exact level of the parameter in the system, as well as to immediately respond in case of a problem.

The principle of operation of electronic and mechanical oil pressure sensors

The principle of operation of the oil pressure sensor depends on its type, so we will consider each process separately. For example, a remote electronic DDM is simpler in design, unlike a mechanical one, respectively, the likelihood that a digital controller will fail is very low. The main purpose of the digital DDM is to check the pressure, as well as transfer to the control panel located in the passenger compartment of the car information that the pressure has disappeared.

By design, the digital DDM, which is located in the engine, consists of the following components:

• frame;
• membrane;
• contacts;
• as well as a pusher device.

The digital oil pressure sensor must be connected to the car's on-board network. In particular, we are talking about the section of the chain, where the emergency indicator is also located. When the digital DDM is not working, that is, the engine is turned off, its membrane is straightened, the pusher device is pushed into its original position, and the contacts themselves are closed. If in this state you decide to connect a digital DDM, then the emergency pressure indicator located on the circuit section will begin to function - it lights up, blinks and blinks.

Accordingly, when the motor starts, when the unit is started, the light is always on at the very beginning. When the internal combustion engine is started, the pressure of the working fluid appears in the system, which, in turn, begins to act on the membrane. This element begins to interact with the pusher device, which opens the contacts. In the event that the parameter starts to decrease, the contacts of the digital DDM will close again - at this moment, the emergency lamp is on, flashing or blinking on the instrument panel. It should be noted that if the device itself breaks down, then the lamp blinks, blinks or just burns.

As for the two-pin analog mechanical device, then such a device has more complex structure. The mechanical oil pressure sensor, in addition to the membrane, housing and pusher device, also has a slider and a nichrome winding in its design. In addition, two-pin analog mechanical sensor oil pressure also has several components in its design. It must be borne in mind that if these components fail or their incorrect operation, the regulator will display incorrect information on the dashboard of the car or even fail.

As for the principle of operation of a two-pin or any other mechanical device, it is also slightly different. The data on the pointer is received depending on the position of the slider on the plate with a nichrome winding. In the event that the engine fluid acts on the membrane under pressure, it begins to actuate the pusher device. Ultimately, the data from this component is transmitted to the node for changing the resistance level, and the pressure data directly goes to the dial indicator on the control panel.

DDM Verification Guide

How to properly check the oil pressure sensor? Diagnostic options differ depending on the type of regulator.

Diagnostics of the electronic sensor

To diagnose an electronic DDM engine, you will need a multimeter, as well as a pump, while it is desirable that the pump be equipped with a pressure gauge. Before proceeding with the diagnosis, it is necessary to dismantle the DDM from the car, and then activate the multimeter in the mode of checking the wiring for a break. The engine DDM must be connected to the pump, and a multimeter must also be connected to it. The use of a pressure gauge in this case is very important, because with its help you can adjust the pressure parameter and not give too much, otherwise the regulator may simply break (the author of the video is SamodelTV).

So, having connected the pump with a pressure gauge and a multimeter to the regulator, you need to make sure that the arrow on the scale of the device is at zero. After these steps, you need to apply a minimum pressure from the pump itself, as a result, if the engine DDM is working, its membrane will bend and start moving the pusher. Accordingly, as a result, the circuit should open, which will contribute to the deviation of the arrow on the device, namely, towards infinity. In order not to doubt the performance of the regulator, you can try to give the maximum pressure (or rather, as close as possible to this indicator).

Diagnosis of mechanical DDM

As for diagnostics mechanical regulator, then in general this procedure is similar to the above, but there are some differences. First of all, to get more accurate results, you will need a pump, also equipped with a pressure gauge and a rubber hose (small). To check, DDM must be dismantled from the motor along with the arrow scale. It is necessary to install and put the pump to the regulator in such a way that the connection point is the most tight. In the event that you are sure that, as a result of installation, the connection of the elements is hermetic, you can proceed to the test (the author of the video is Kirill Zbruenko).

The essence of the diagnosis is to supply air with a pump through the DDM, while the pressure parameter, which should be different, must be controlled by a pressure gauge. When the maximum and minimum parameters are applied, the obtained indicators must be recorded, while fixing the resistance level. After several indicators are recorded, they must be compared with a table that indicates optimal values. These values ​​are indicated in the service manual, we will not write about them, since they differ depending on the vehicle model.

Do-it-yourself sensor replacement

Why is the oil pressure sensor replaced?

There may be several reasons for this:

1. The regulator is leaking. It doesn't matter on idling or when driving, often drivers encounter a problem when the device is leaking. In this case, it does not matter whether the lamp on the control panel is on or not when DDM is flowing. In any case, if the regulator is leaking, it indicates a bad connection.
2. The lamp on the dashboard is on. At the same time, diagnostics power unit showed that it works well.

We figured out why it is necessary to change the DDM, now we will consider the question of how the oil pressure sensor is replaced.

The process is considered on the example of a VAZ 2109 car:

1. First of all, the device is dismantled. From DDM it is necessary to disconnect the wire leading to it with a protective cover.
2. After that, using a wrench, you must completely unscrew the DDM. After unscrewing the regulator is removed from the seat.
3. Now installation. A new DDM is taken, it must be put in the landing nest.
4. After installation, the regulator must be tightened as far as it will go, for this a wrench is used.
5. When you managed to install and tighten the DDM as much as possible, connect the disconnected cable to it along with the cover.

When purchasing DDM in a store, you need to pay attention to its labeling. If there are differences in the markings of the replaced devices, the new device may not work correctly.

Video "We replace the sensor with our own hands"

How the process of replacing the sensor is carried out - look at the video (the author of the video is Auto_Repair).

In this article, we will look at why oil pressure in the engine may disappear and how to fix this problem. So, there is no oil pressure in the engine, a red light on the tidy signals this, which makes the owner of the car very sad. Let's say right away that you can’t go with this problem, because you risk getting a big blow to your pocket after a couple of kilometers, if not earlier.

What are the consequences of driving with no oil pressure? Well, in general, there is little pleasant, starting from a jammed crankshaft, ending with its bifurcation in half, and other serious problems. However, read about everything here. Well, apart from unpleasant moments, such as accompanying adventures with driving to services, specialists in spare parts stores, in order to buy often by no means cheap spare parts, and finally - time. So one hundred, as your oil pressure lamp lights up, then the car is immediately in tow and forward to look for and eliminate the cause.

In general, there are few reasons, we will try to consider them all here. So:

The lack of oil pressure in the engine may be due to the following reasons

* Faulty oil pump. It happens suddenly, or, due to the fact that during the repair they did not inspect, that is, they put a knowingly faulty pump on the motor.
* Faulty oil pressure sensor. The reasons for this are also many and difficult to think of.
* It may be due to a large oil leak from the line, it can both go out and in.
* Low oil level, also due to oil dilution.
* Finally, the oil line and/or oil filter is clogged.

About oil pump malfunction

As practice shows, it can arise from nowhere, suddenly, while driving, and, as a rule, the driver most often does not have time to “calculate” the pressure loss in right time, and the appearance of a knock turns off the engine after, which, as mentioned above, causes a bunch of problems in the future. And the very reason for the loss of pressure can show an autopsy. So, there is no oil pressure in the engine after its repair, here you should know why the repair was made, if the engine knocked before, they didn’t check the pump and didn’t change it, that’s the reason for you, but only amateurs and lazy people do this. As a rule, during the repair, the oil pump is checked in without fail, because it is the heart of the motor, and in many ways it depends on it how long the engine will last.

By the way, here is a story from the distant past of one specialist minder. When he was just starting to repair motors. There was a case with the BeEmVe 316, however, he does not remember exactly which engine model, he knows only a 1.6-liter volume, one of the ancient models is a relative of the “Moskvich” one. In general, they made repairs to it, the engine was removed, the rings and liners were sorted out, the seals were updated, assembled and put back. Then the master was not yet experienced, at their service they poured antifreeze and oil, and began to start the engine, it started up, however, there was no oil pressure! For a long time they did not understand what was the matter, they removed the frontal part, since it has a pump in the frontal part, they spun it with a drill - somehow. It turned out that everything seemed to be in order, there was a little shabby cover, which pressed the gears, and the gears themselves, in turn, were in in perfect order. However - not a drop of oil, everything was absolutely dry there. In general, they didn’t find anything and decided that they should pour a little oil into the pump itself, filled it in, put everything back, of course, it wasn’t without effort, it wasn’t to break or build. Before starting the engine, they poured oil into the filter, since the filter is located on top of it. After some time, the oil quickly left, and then stopped, and the masters decided that it was time, they started the engine with the filter cover open, first air bubbles began to flow, and then finally the oil left, they were happy at that moment! For they had a lot of nerves, that motor patted them, I quote: "thanks to their stupidity and ignorance." So you need to know that before you install the oil pump, you MUST first fill it with a small amount of oil, learn from such mistakes and avoid your own. Although, if you are reading this, then most likely you have already done your own. And finally, be sure to check the oil pump drive, since, as already mentioned about the KAMAZ engine oil pump and its repair.

About malfunctions of the oil pressure sensor

There are several reasons for this, depending on what type of sensor, whether it is electronic or mechanical. If it is of the electronic type, then you should first of all check the wire, as well as its connection with the sensor itself, for the quality of the connection, and if the wire is mixed up. If the sensor is mechanical, as for example on KamAZ trucks or other cars of the USSR era, then we unscrew the hose or tube through which oil is supplied to the sensor, check for clogging. If everything is clean and the sensor does not show anything, it means that everything is very bad! You should also not exclude the fact that the sensor itself has failed, and no matter what type it is, you can check it by updating the sensor to a known good one, or connect a special pressure gauge at the place where the sensor is twisted, start the engine and monitor the pressure gauge readings. If there is pressure, then we change the sensor, if not, then things are very bad. Yes, by the way, not everyone will be able to "calculate" and recognize the same oil pressure sensor on engines, especially on "foreign" ones. On all "engines" it can be installed in different places, however, even taking this into account, it is screwed, as a rule, in the immediate vicinity of the oil filter, or somewhere in the side oil line.

About oil leakage from the highway

A leak can be small, barely noticeable, or completely invisible, and it’s not scary if it is inside the engine. It will be scary if outside, and even while driving, then it’s really AHTUNG !!! The motor runs the risk of being completely without oil. Further, one of the reasons may be the fact that the rubber band can be squeezed out from under the filter. Or the appearance of a hole in the filter. A real case with an Audi A6 with a similar case, the owner just bought it, traveled for a month, and suddenly oil slowly began to drip, from where exactly, they could not figure it out for two days. Only in the morning it dripped when you start the engine in the cold, it drips for five minutes and stops, and it doesn’t drip anymore, say, until you get to the pit. As it turned out, the oil filter was rusted, apparently when they changed it, they damaged the paint with a key, and after that it began to slowly rot. Leakage inside can occur due to worn parts of the crankshaft, especially the crankshaft main bearings, as well as due to the bushings of the camshafts and balance shafts. If the pressure reducing valve is stuck on the oil pump, then the lion's share of the oil will be dumped directly into the sump, this probably should have been attributed to malfunctions or malfunctions of the pump, but oh well. So, in general, one can fantasize about leaks, only at the expense of knowledge of the features of the anatomy and structure of our “patient”.

About clogged filters and oil lines

It happens, of course, this, but sometimes, when for some reason this happens, but there were still cases. So, the oil line may become clogged or some kind of debris that was poured into your engine by some ill-wisher. Or the soot that has accumulated in the engine, which has never, or for a very long time, seen repairs. Spare parts are quite often improperly stored, which is especially true for our collective farmers, and at the crucial moment of demand, pigeons pissed on them. And in the oil lines, all sorts of insects and sikarashki registered! So, if an amateur is taken to assemble a motor from such a pile of spare parts, then he will be on the drum that the block, which is unclear how long, has become an apartment for many insects, which naturally left a lot of their metabolic products in it.

Such people quite often wash such blocks inside and out, but unwind the oil lines and check, clean, somehow the hand doesn’t reach or it’s not fate. Then they come and say that they have assembled a pressure block, but there is no oil, help, tell me - what is the reason, and no one admits that the block is poorly cleaned, because these are “superspecialists”. A clogged filter can also be the cause. When the filter is clogged, the oil pressure through the pressure reducing valve will be released, and the motor will not see oil. And again, why can the oil filter become clogged? Yes, everything is simple - thanks to cheap oil of who knows what origin, which burns in the engine, leaving plaque and soot everywhere behind it, which is washed off with oil over time (it doesn’t matter with the same oil, or if normal oil has already been poured) and the filter becomes clogged with its solid particles. Or again, someone “added something” and “added” something to your motor.

Filters also become clogged, causing oil pressure to be lost, again thanks to amateur motorists. Here is another case from life, a YaMZ-238 engine was brought from a distant village, already with a rag filter and an electric fan clutch, complaining that they had already done it twice, and it didn’t have time to get to the field - it immediately knocks. Ok, they brought it, the masters went over it, cleaned the filter, and it turned out that an ordinary rag (!!!) was wound around the filter housing, which eventually became resinous, stiff, reaching the state of "papier mache" which reached a quality of very thick cardboard, that's the very reason why there was no oil pressure in the engine. And these “jack of all trades” have already capitalized the motor twice, and no one thought of looking into the oil filter!

Oil thinning

This phenomenon occurs most often when fuel gets into the oil, we also already wrote about this, with examples, and you can read this article here. It should be added that when oil dilution occurs, the pressure does not immediately disappear, it decreases gradually, as a result, at one moment the oil pressure lamp will start to signal, but by that time the engine already needs to be overhauled, whether you want it or not.

And as a verdict, I would like to say, monitor the condition of the engine of your car, fix all malfunctions and carry out maintenance in a timely manner, do not be amateurs and unfortunate drivers, after all.

The operation of the car engine is impossible without oil system. It is necessary to supply oil to the rubbing parts of the motor, which reduces their wear, as well as cool them to prevent overheating. Every driver knows that it is necessary to monitor the level and quality of the oil in the engine, but some forget about another important indicator of the oil system - pressure.

The system of mechanisms in the oil system maintains its pressure during engine operation. Due to this, lubricants reach all important elements engine, acting on them necessary. You can check the oil level in the engine using a dipstick, and special sensors are used to control pressure. If they fail, the driver will no longer understand whether sufficient pressure is created in the oil system and whether the engine parts are lubricated as necessary. This can lead to serious problems, up to engine failure, so it is important to as soon as possible replace pressure sensors if they are defective.

Types of oil pressure sensors

Two types of oil pressure sensors have found application in the automotive industry:

• Electronic, which is often called emergency. It is able to work in two modes: yes / no. That is, it is impossible to achieve accurate indicators from such a sensor, and its task is to signal to the driver that the oil pressure in the engine has completely disappeared.
• Mechanical. Unlike electronic, it allows you to accurately determine the oil pressure, which the driver is informed about by an arrow scale on the instrument panel.

Some vehicles use two types of sensors at the same time, allowing drivers to monitor precise oil pressure and react instantly if it drops to zero.

How Oil Pressure Sensors Work

Depending on which oil pressure sensor is used in the car, the principles of their operation differ.

The principle of operation of the electronic oil pressure sensor

An electronic oil pressure sensor is much simpler than a mechanical one, and its failure is less likely. The task of the sensor is to transmit information to the driver's dashboard that the pressure has stopped flowing. Such a sensor consists of the following elements: housing, membrane, contacts and pusher. The sensor is included in the electrical circuit, which also contains an emergency pressure indicator.

In the idle state of the engine, the membrane is straightened, the pusher is retracted and the contacts are closed. If the sensor is energized at this moment, the emergency pressure indicator will light up. That is why when starting the engine, the light is on at the very beginning. When the motor starts, oil pressure arises, which acts on the membrane, and it interacts with the pusher, which opens the contacts. If the pressure is lost, the contacts will close again, and the driver's alarm indicator will light up on the dashboard. Also, the indicator may light when the sensor fails.

The principle of operation of a mechanical oil pressure sensor

The mechanical oil pressure sensor is more complex, and it includes the following key components: a housing, a diaphragm, a pushrod, a slider, and a nichrome winding. In addition, there are several small elements in the design of the sensor, if they fail, it will show incorrect data or stop working altogether.

The principle of operation of a mechanical sensor is that information is sent to the oil pressure gauge on the instrument panel, depending on the position of the slider on the plate with a nichrome winding. When pressurized oil acts on the diaphragm, it drives the pushrod. From it, the pressure is transmitted to the resistance change mechanism, and information about the pressure is sent to the dial indicator on the instrument panel.

How to check the electronic oil pressure sensor

To check electronic sensor pressure, you will need a multimeter and a pump (preferably with a pressure gauge). Before starting the test, it is necessary to remove the sensor from the car and switch the multimeter to the “open” circuit diagnostic mode. Connect the sensor to the pump and connect a multimeter to it. It is better to use a pump with a pressure gauge so as not to apply excess pressure, from which electronic device will fail.

By combining the pump, pressure gauge and multimeter, make sure that the arrow on the scale is at zero. Next, apply the minimum pressure from the pump, as a result of which the membrane on the working sensor should bend, move the pusher and the circuit will open, which will lead to the deviation of the arrow of the device towards infinity. It is also recommended to apply pressure close to the maximum, and make sure that the sensor is working in this mode.

How to test a mechanical oil pressure sensor

The principle of checking a mechanical oil pressure sensor is practically the same as diagnosing an electronic version. To carry out the procedure, you will need a pump with a pressure gauge and a small rubber hose. When checking, the sensor must be removed together with the pointer. The pump is connected to the sensor using rubber hose and the connection must be airtight. When everything is connected, it is necessary to start applying various pressures, controlling it on a pressure gauge. At the moment a certain pressure is applied, its value is recorded and the resistance is also fixed. When several values ​​are taken, it is possible to compare the obtained data with a table of ideal values, which differs from car to car, and can be found from technical documentation to the car or on the Internet.

The question is how to check oil pressure sensor(hereinafter DDM) is of interest to drivers who have encountered problems in the operation of the engine oil system, in particular when. You can check this assembly using an electronic or arrow multimeter, a control light or a working pressure gauge. The verification procedure is simple, and even a novice motorist can do it. The following are detailed verification algorithms indicating the subtleties and nuances.

The principle of operation of the oil pressure sensor

Before you figure out how you can check the DDM, you need to briefly dwell on the theory, in particular, how the oil pressure sensor works. This will give a complete understanding of the process. First of all, it must be pointed out that oil pressure sensors are of two types - mechanical (installed on old cars, in particular, Soviet models) and electronic (more modern, widely used in the automotive industry).

Design of mechanical sensors

Mechanical DDM device

Inside the mechanical sensor there is a membrane that changes its shape depending on the pressure applied to it. Accordingly, the larger it is, the more the membrane bends. Bending, it acts on the rod in the design, which is responsible for compressing the liquid in a special sealed tube. At the other end of this tube is a rod on which this liquid pressed, and now the second rod moved the arrow of the device - a differential pressure gauge, or just a pressure gauge. The pressure increases - the arrow goes up, the pressure drops - the arrow goes down.

There is also another, more common mechanical oil pressure sensor device. It is similar, but with the addition of a variable resistor - a rheostat. So, a resistor is placed on the membrane in its design, which changes its resistance depending on, in fact, the value of the applied efforts. Accordingly, the greater the deformation of the membrane, the greater the change in the resistance of the sensor. In the absence of membrane deformation, the resistance value will be zero. This change is fixed by the electronic engine control unit (ECU), to which the corresponding signal is given. His software created in such a way that it controls the presence of the signal from the DDM in a certain interval corresponding to the normal operating oil pressure in the engine oil system. As a rule, dial gauges are attached to mechanical sensors, on the scale of which the absolute value of the oil is shown. Although in fact these devices are voltmeters, the arrow of which changes its position in accordance with the resistance value coming to the device from the DDM.

Design of the electronic sensor

Electric DDM device. 1 - rod, 2 - signal lamp, 3 - contacts, 4 - membrane

The design of the electronic oil pressure sensor (by the way, it is installed on VAZ-2114 cars and its analogues, the new Lada models) implies that with an even membrane (not under pressure), the signal lamp supply circuit on the instrument panel is normally closed, so it turns on under the appropriate conditions. However, when the diaphragm flexes under the action of oil pressure, it mechanically opens the circuit with its rod and the signal lamp goes out. This, in fact, happens when the engine is started, which can be judged by the fact that the oiler lamp with the ignition on, as well as the first 1 ... 2 seconds, is in the active state (lights up).

Thus, the essence of checking a modern DDM is to measure the resistance of the sensor winding with a multimeter switched to the mode of measuring electrical resistance (ohmmeter). However, it can also be tested in other ways.

Sensor Diagnostics

As mentioned above, there are two types of pressure sensors - mechanical and electronic. Accordingly, the procedures for checking the emergency oil pressure sensor in both cases will differ, albeit slightly (there are only design features sensor data). First of all, you need to make sure that it is the oil pressure sensor that is faulty. To do this, you will need to perform additional diagnostics of the oil system - check the oil level in it, the condition of the filter, pump, and so on. If suspicions fell precisely on the serviceability of the oil pressure sensor, then first of all it is necessary to dismantle it from the seat with the engine turned off (as a rule, it is located in the area of ​​\u200b\u200bthe oil filter).

Usually, keys of various diameters are used for this, for example, 24, 27 or others (depending on the specific car model). After that don't forget to shut it up seat rags so that when the engine is running, oil does not flow out of it, and various debris or small parts (bolts, nuts, etc.) do not get into the oil system!

It is also advisable to check the pressure in the oil system of the car. To do this, you need to screw a pressure gauge into the seat from where the DDM was unscrewed, with which you can make control measurement oil pressure at various engine speeds. Please note that in this case it is necessary to ensure maximum tightness so that the pressure gauge readings are extremely accurate. Be sure to look at the pressure when the engine is idling, as well as at medium and high.

For different machines, the value of the corresponding pressure will be different, so you will find the exact information in the manual or technical documentation for a particular machine. If the pressure value is normal, but the information does not reach the computer, then the sensor is most likely to blame, so it needs to be checked.

Checking the electric oil pressure sensor

Checking the sensor with a multimeter

Electronic oil pressure sensors used both on foreign cars and domestic cars, in particular, on VAZ-2114 and other modern Ladakh cars, are easy to check. Their device is similar to that where a rheostat is used, however, they simply open the circuit at a certain pressure. Accordingly, its verification is even easier. For this you need:

• Set the multimeter to the "continuity" (break) mode of the electrical circuit.
• Ensure a tight connection air pump and an inlet (sensitive) hole where air is supplied. Here, similarly, it is necessary to ensure high-quality sealing, since the result of the experiment directly depends on this.
• Install one multimeter probe on the central output contact of the sensor, and the second on its body, "ground".
• At the same time, apply an air pressure of about 1 ... 1.5 atmospheres to the sensor using a pump. It is not necessary to blow strongly, so as not to damage the membrane. If the sensor is correct, then electrical circuit will open almost immediately, under the mechanical action of the rod, which is in rigid connection with the flexible sensitive membrane of the oil pressure sensor.

As is clear from the diagram of the sensor, if the circuit is open (fixed by a multimeter), then the sensor is working. Otherwise, no. In rare cases, instead of a sensor, the problem of why the oil light is on must be sought in faulty (broken or damaged insulation) wiring.

Also, the performance of the oil pressure sensor can be checked by another method. So, you need to remove the power wire from the sensor and short it to ground. If the sensor is working, then the signal light on the dashboard should not light up. Otherwise, the sensor is defective.

Checking two sensors

On some modern machines install two identical ("new") pressure sensors. The first is designed for an absolute pressure value in the range of about 0.15 ... 0.45 atmospheres, and is designed to open the control lamp after the engine is started. Its verification is similar, and corresponds to the procedure described above. That is, the connection is the same. Its circuit should open when pressure is built up in it in the specified range.

The second sensor is designed to monitor oil pressure on a running engine. It is similar in type to the first, but its difference lies in controlling the upper limit of the oil (in order to prevent it from increasing to a critical value). The upper value can be different, and is different for specific models cars. However, in most cases it is about 1.8 atmospheres. When this pressure level or above is reached, the contact circuit should be closed, and accordingly, the oil pressure warning lamp in the engine system should be activated on the instrument panel.

Checking the pressure sensor with a light bulb

To check an electrical (new) oil pressure sensor, instead of a multimeter, you can use a light bulb designed to operate under a voltage of 12 V DC, as well as a power supply (battery) and a compressor (preferably with a pressure gauge). The verification algorithm is as follows:

Wiring diagram

• Two wires must be connected to the contacts of the light bulb.
• Connect one of the ends of the wire going to the bulb to the output contact of the pressure sensor.
• Connect the ground from the power supply unit (or minus from the battery), respectively, to the body (ground) of the sensor.
• Connect the plus from the power supply or battery to the other wire on the light bulb.
• If the sensor is working, then after turning on the power supply (or just when contact occurs from the battery), the light should light up. Otherwise, the sensor can immediately be considered faulty.
• Further, for verification, it is necessary to apply a pressure of about 0.5 atmospheres to the sensitive element of the sensor using a compressor or pump. The pressure value can be different, and it depends on what kind of pressure the sensor is designed for. Usually it is around the already mentioned 0.5 atmosphere.
• When the pressure rises to the specified value (critical for the sensor), the light should go out, because this will open the control circuit in the sensor housing. If this does not happen, then the sensor can also be considered unusable.

Instead of a compressor, it is quite possible to get by with an ordinary automobile and even a bicycle pump, which will give out the necessary air pressure atmospheres without any problems.

Checking the mechanical sensor

Checking an old mechanical sensor (for example, installed on some VAZ "classic" models and old foreign cars, for example, "Volvo 240"), with which it is possible to directly find out what pressure is currently in the car's oil system, can be done even without multimeter, but using additional devices(air pump and electric car pressure gauge). Similarly, the sensor must be removed from the machine, since it will not work to check it directly on the engine.

Checking the sensor with a pressure gauge

Verification is a little more complicated than that of electronic ones, but this consists, first of all, in some difficulty in assembling an electrical circuit. You need to act according to the following algorithm:

How to check a mechanical sensor, wiring diagram

• On the sensor, you need to find a contact that gives a signal for an emergency oil pressure lamp on the dashboard of the car, as well as another contact, from where a signal is given to indicate oil pressure. "Mass" for further measurements will simply need to be taken from the sensor housing (under normal conditions, all sensors take "mass" simply from the engine housing).
• Similarly, on an electronic pressure gauge, you need to figure out where to connect the plus and minus of its power supply, as well as directly the signal from the sensor (that is, there are three contacts).
• To plug wiring diagram, and tightly connect the air hose connecting the pump and the sensing element of the sensor.
• Next, you need to apply 1 ... 2 atmospheres to the sensitive element of the sensor using a pump. If it is working, then the incoming pressure will be clearly shown on the dial gauge. If this does not happen, then the oil pressure sensor is faulty.

As a rule, oil pressure sensors cannot be repaired, so if their malfunction has been identified, then this assembly must be replaced. Fortunately, these elements are inexpensive and are available everywhere in almost any car shop.

Please note that when mounting the sensor on its seat after checking, it is recommended to lubricate it.

One head it's good, but two better

On numerous forums on the Internet, you can often find stories from experienced motorists that, together with an electronic oil pressure sensor, they installed a mechanical one in parallel with it. In particular, this is expressed in the fact that in the event of a drop in the oil pressure level, not only the corresponding control lamp on the dashboard lights up, but the absolute value of the pressure on the pressure gauge installed somewhere near the dashboard will also be visible.

This is done for the reason that sometimes, for example, after running on the engine overhaul or when using low-quality (or outdated) engine oil that has clumped, the sensor's sensing element does not work properly, respectively. Accordingly, when the pressure drops, the control lamp does not light up, which is a critical fact, since the engine runs “dry” under such conditions, that is, without proper lubrication. This significantly reduces its resource and can completely disable the motor in the shortest possible time.

So, motorists install a so-called tee at the connection point of the pressure sensor, a traditional electronic sensor is connected to one output end of which, and a mechanical one to the other. The hose with wires is mounted in the engine compartment in accordance with the design of the engine. The main thing is that it does not interfere with other elements of the motor, and itself is not subjected to mechanical and significant thermal effects. A pressure gauge is installed at its end, for example, from a VAZ "classic", UAZ or other similar device. In fact, his model is not important, the main thing is that it is convenient to navigate on a scale, that is, it must have detailed graduation.

Conclusion

Pressure sensor - enough reliable knot and rarely fails. Therefore, if problems arise with the oil system indication system, it is necessary to check other parameters - oil pressure, leaks, the condition of the oil itself, its level and the oil filter, and only after that check the condition of the oil pressure sensor. In general, checking the health of this unit is not very difficult, and even novice motorists can do it, literally using a car compressor and a multimeter. If the sensor is out of order, then it is hardly possible to repair it, so it is better to buy a new DDM in a car shop, since it is inexpensive.

(!LANG:Oil pressure sensor malfunction

A drop in engine oil pressure in an engine can be catastrophic. If the oil pressure warning light on the dashboard turns on, the driver must clearly understand what is wrong and find out whether there really is a problem with the engine, or whether it is a malfunction of the oil pressure sensor. Paying attention to certain signs, you can easily determine what exactly (oil pressure sensor or something else) led to the problem.

Sudden drop in oil pressure

While the vehicle is moving, the needle on the oil pressure gauge should be within the normal range. A sharp movement of the arrow to zero clearly indicates the occurrence of some kind of problem. According to data from the University of Wisconsin Research, this movement of the oil pressure gauge needle may be due to the failure of the oil pressure sensor or the pressure gauge itself, as well as damage to the electrical wiring.

Unstable readings on the oil pressure gauge

An unstable reading on the oil gauge is another sign of a bad oil pressure sensor. When the engine is running, the pressure gauge needle may first be in the normal range, and then suddenly begin to oscillate randomly. The pointer can move sharply from zero to maximum pressure and back, and it can also move within the entire range.

Excessive oil pressure

The next symptom of a sensor malfunction is a reading that is too high pressure oils. In this case, the arrow on the oil pressure gauge will move sharply and stop at the maximum pressure mark. In this case, the oil pressure sensor will “jam” in the “open” position, which will send a false signal about pump overload or blockage safety valve pressure in the closed position.

Testing and replacement