The dashboard of any car includes several alarm indicators that signal a malfunction of a particular system. One of them is the engine oil pressure lamp, traditionally painted red. If it is on or flashing during operation power unit, the owner of the car must immediately find out the cause of the problem and take measures to eliminate it. Ignoring the signal in the vast majority of cases leads to serious consequences, so it will be useful for motorists to know what to do in such a situation.
The red light, marked on many cars with the oil can, was added to the dashboard for a reason. It is connected to a common electrical circuit with a sensor mounted in one of the channels of the engine lubrication system. When the element detects a pressure drop below a critical level, the circuit closes and the lamp flashes red, informing the driver of an emergency fault.
The signal of the red lamp with the image of the oil can indicates a malfunction of the engine lubrication system
In some modern cars the power unit is equipped with not one, but two sensors: high and low pressure motor lubricant... The first monitors the operation of the motor under load, the second - on idle... Both elements are included in a circuit with one indicator that reacts to pulses coming from them. The response thresholds are 1.8 and 0.3 bar, respectively.
Task emergency lamp - warn the motorist about oil starvation in time. If, for various reasons, it does not light up or the driver ignores the red signal of the "oiler" on the instrument panel, then the following consequences may occur:
Insufficient or lack of lubrication in any case leads to breakdown and costly repairs to the power unit. Timely signal on dashboard will help to avoid this.
What the lamp signals
The indicator on the dashboard reacts strictly to the engine oil pressure. Due to a reasonable decrease in the level, the signal on the panel will not appear. An exception is the loss of 2/3 of the lubricant when the pump oil intake begins to pick up air and blow-by gases. Then the pressure in the lubricating channels will inevitably drop, to which the sensor will react and the lamp will light up.
When the level in the sump drops to a critical mark, the pump draws in oil at different rates due to vibration and vehicle movement. "Oiler" on the dashboard starts blinking, and when the level drops further, it will light up constantly.
The oil receiver is specially installed at the bottom of the sump so that the system works when there is a lack of lubrication A circuit that signals powertrain lubrication problems consists of parts that also break down periodically. So the flashing of the lamp does not always mean fatal damage to the motor. But if it caught fire on your car, then you need to act like this:
In the garage, you can locate the cause of the alarm if you follow the steps below.
Video: a light bulb lit up on the way - what to do
Diagnostics of faults and methods of elimination
There are quite a few reasons why the red "oil can" lights up on the dashboard. One of them was mentioned above - the loss of a large amount of lubricant. This happens as a result of a sump breakdown or through the negligence of a motorist who does not notice oil burnout in the cylinders due to critical wear of the piston group.
The lack of engine lubricating fluid is determined simply: after stopping the engine, wait 10 minutes for it to drain into the crankcase, and measure the level with a dipstick. An oil limit below the Min mark indicates a shortage (but there is still lubricant in the engine), and a dry dipstick indicates a lack of lubricant (you cannot go further).
If the oil level in the crankcase is low, an immediate top-up is required The rest of the reasons look like this:
- failure of the pressure sensor;
- insufficient oil viscosity;
- increased wear of sleeve bearings (liners) crankshaft;
- oil pump malfunction.
When the warning light is on, topping up the oil to the norm can increase the pressure If checking the level or adding engine lubricant does not give a result and the lamp is still on, take the car to the garage and proceed with the diagnosis.
Sensor check
A failed element or poor contact in the electrical circuit can cause the indicator to flash at any time: on a warm and cold engine, during driving and at idle. In order to immediately cut off this symptom in the diagnostic process, it is necessary to measure the real oil pressure directly.
To measure, you need the following tools and devices:
Allow the engine to cool before starting the test so that you do not have to burn your hands during disassembly. Then find the sensor - on most cars, it is screwed into the cylinder head or top of the block. For example, in "Zhiguli" the device is on the left side of the cylinder block (in the direction of travel), and in front-wheel drive VAZs - on the rear wall of the engine.
In VAZ 2101–07 cars, the pressure sensor is installed on the left wall of the cylinder block The diagnostic procedure is as follows:
If the readings of the device are equal or more than the indicated values, feel free to change the sensor. Just first check the integrity of the wiring with a multimeter so that you don't have to buy an element in vain because of a broken wire. If there is no minimum pressure, proceed to the next test step.
There is an old way to make sure that the lubrication system of VAZ cars is working. Open the filler neck on valve cover, start the engine and bring a sheet of paper. If there are drops of splashed oil on it, then the system is functioning. But you still need to make a measurement with a pressure gauge.
Video: detecting sensor breakage and replacing it
Change in oil viscosity
Filling the engine with a lubricant of a different viscosity makes itself felt immediately. The signs are as follows:
- Thicker oil causes a pressure jump when starting a cold engine, the light goes out at idle. After warming up, the material liquefies, but the sensor still does not work. The actual head value can only be found with a mechanical pressure gauge.
- Too liquid lubricant can cause the indicator to flash or light at idle, and at 1500-2000 rpm the lamp goes out. This pattern is observed on a "hot" motor, but on a cold one there is no alarm signal.
The behavior of the indicator depends on the consistency of the lubricant. Due to too liquid oil, the lamp may flare up even "cold".
Unburned gasoline flows down the cylinder walls into the oil pan and dilutes the oil A more insidious malfunction that causes the alarm to flash is the failure of the spark plugs or the fuel supply system. In the first case air-fuel mixture does not burn completely in the chambers, and in the second, the leaking nozzles literally fill the cylinders. In both cases, unburned gasoline flows into the crankcase, mixes with the engine oil and dilutes it, causing the pressure to drop and the oil can flares up.
Gasoline flowing into the pan is characterized by the following features:
- the indicator blinks after warming up at low engine speeds, at high speeds it goes out;
- when the accelerator pedal is pressed, a failure is observed - the motor "suffocates" from over-enrichment of the mixture;
- "Cold" there are no malfunction symptoms.
It is simple to make sure of the problem: with the engine running warm, remove the hose leading from the crankcase to the air duct throttle (or to air filter on the carburetor). If the operation of the engine evens out, and a sharp smell of gasoline comes from the removed pipe, then the reason is in it. Repair the fuel system and install new spark plugs, then change the engine lubricant.
To detect fuel in oil, remove the crankcase ventilation pipe If, for various reasons, you forgot to change the oil on time and continue to drive, the flashing red signal of the "oiler" will remind you that the material has developed lubricating properties and turned into black water.
Engine problems
These are the most serious malfunctions associated with wear of engine parts. They are characterized by the constant burning of the oil pressure lamp in all modes, including on the go. An additional feature is a thud at the bottom of the cylinder block. What can cause:
To get to the oil pump and crankshaft, it is necessary to unscrew and remove the pan Most of the listed problems require the intervention of a master - minder. The exception is a crumpled pallet (to be replaced) and a clogged net, which you can clean yourself. To do this, you have to unscrew the motor from the pillows, raise it with a jack and dismantle the oil pan. An autopsy will surely show whether the repair will cost one cleaning or it is necessary to remove the pump and conduct its revision.
As a rule, trouble does not come alone. A large amount of dirt, carbon deposits and shavings accumulated in the crankcase of the power unit and is able to tightly clog the oil pump sieve is the result high mileage motor. If you see a similar picture on your car, it is worth considering a partial or major engine overhaul.
Video: oil pump repair and pressure restoration
The attitude towards an illuminated lamp indicating a drop in oil pressure must be extremely serious. Have you noticed a signal - play it safe and turn off the engine until diagnostics. Do not rely on a sensor malfunction - this is a reliable part and breaks down infrequently. And the best way to avoid the appearance of a red "oil can" on the dashboard for a longer time is to fill in a high-quality lubricantrecommended by the manufacturer. And do it on time.
Oil light at running engine and a sufficient level of lubricant is inactive, that is, does not light up. If it lights up, this indicates malfunctions taking place, such as low oil level in the crankcase, low pressure in oil system engine (for example, the oil filter is clogged, does not work well oil pump), the oil level sensor has failed, and some others, less common. In any case, if the oil pressure light is on or blinking, you must first check the level of the lubricating fluid. If its indicator is normal, then you need to look for the reason that caused such an indication and eliminate it.
What to do when the oil light is on
Now that we have considered the reasons why the oil level light may come on, we can move on to the question of what to do in such a situation. First of all, you need to understand that specific actions directly depend on the reasons why this situation happened. Therefore, we will give the algorithms of actions in the same sequence as the reasons.
Low oil level... The sequence of actions here depends on the situation in which the red oil light is on. The easiest option is that it caught fire in the garage or parking lot when the engine was started. In this case, turn off the engine again, open the hood, and use a dipstick to measure the oil level in the crankcase. If it is not enough, then you just need to add lubricant approximately 90 ... 95% between the MIN and MAX marks (this is harmful to the oil system).
When measuring the oil level, the machine must stand on a horizontal surface! In addition, level measurements must be carried out regularly, and not only when the oil light comes on!
It is advisable to top up with the same lubricating fluid that was poured in earlier. To do this, it is better to always have with you in the canister the leftover oil that was filled during replacement. Mixing oils is acceptable, but not desirable. And if you mix oils of the same viscosity and type, but different brands - that's half the trouble, but if you mix oils different viscositiesand even more so different types (for example, synthetic and semi-synthetic oil), then it is undesirable to ride such a train for a long time. As soon as possible, it is better to replace the lubricating composition of the engine, having previously flushed it with a special one.
Please note that in some cases it is better not to top up, but to completely change the filled oil. First of all, this concerns the situation when it came up according to the regulations.
If the yellow oil light comes on while driving in the city or on the highway and burns on a constant basis, then the actions are similar. Must stop at safe place (on the side of the road, parking), wait a few minutes so that the oil has cooled down a little, and its movement through the system stops. Further, in the same way, using a dipstick, check its level. If you have something to add, then you need to do it. If not, you need to go to a car shop or car service as early as possible and buy (replace) what you need there engine oil... However, you need to drive in an easy mode for the engine, that is, at medium speed and at low speed. If the lamp lights up on the highway, and the store is still far away, then in the most extreme case, you can add others to the engine oil oily liquidseg edible vegetable oil or other similar composition. But of course after that, at the first opportunity, such a slurry will need to be drained and flush the oil system.
Clogged or poor quality oil filter... The situation here is also quite simple. Necessary for off and cooled (!!!) engine dismantle the said filter and check its condition. Accordingly, if it is very dirty, then it is necessary to replace it. Each car has a certain mileage, at which, in accordance with the regulations, it is necessary to change the oil filter. In addition, it necessarily changes with a complete oil change. Additional information for this you will find in the manual for your car.
In addition, you should try to buy quality filters. They, firstly, remove debris from engine oil well (especially if it is also of poor quality), and secondly, they keep a certain oil mass in their volume well, which is necessary for normal engine start-up in order to avoid it. oil starvation in this moment. You can use both original filters, the brand of which can be found in the manual, and their analogs. But at the same time, remember that there is always a chance to run into a fake, regardless of whether it is an original or an analogue.
Faulty pressure reducing valve ... If it fails, you need to dismantle the filter and find the cause of the breakdown. If the spring is really stretched, try to find a similar one and install it on seat... If the valve is heavily clogged with debris, then it needs to be cleaned, and if there is no other damage on it, then reinstall it. In general, to prevent it normal work it is necessary to carry out the work from the previous point - to change the oil filter on time, constantly monitor the condition of the oil and fill in, in fact, a high-quality lubricating fluid, without impurities of solid particles. It is also advisable to flush the oil system before changing the engine oil.
Defective level sensor... If the design of the device is mechanical, then you can try to dismantle and clean it. As a rule, due to dirty oil or for other reasons, its slider stops in one place and does not respond to changing circumstances. A situation may arise that the float “spilled” the oil and sank, respectively, it does not show the real level, but is in the lower position, which is perceived by the ECU as a low level or complete absence oils. It is necessary to revise the sensor, and then reinstall it. Another option is that the wiring from or to the sensor is frayed, that is, it is shorting to ground. Naturally, in such conditions, incorrect signals will go through the wires. If the revision did not help, change the sensor to a new one. If you have no experience in performing the relevant work, it is better to send the car to a car service for service.
Faulty oil pressure sensor... The situation is similar here. It is necessary to revise it. And the performance can be checked using a multimeter and / or pressure gauge. As a rule, if the sensor is out of order, then it only needs to be replaced; unfortunately, it cannot be repaired. In parallel, it is necessary to inspect whether its electrical terminal has not flown off the contact, that is, whether the sensor is connected to the electrical / signaling system of the car, whether signals are sent from it to the ECU.
How to check the oil pressure sensor
To check the correct operation of the oil pressure sensor with your own hands, you will need a multimeter or a control light. The main way to check it is measuring resistance, but you can make sure that it works with a pressure gauge
Clogged mesh of the oil pump... It is necessary to dismantle it and clean it, and then reinstall it. In this case, it is imperative to assess the condition of the oil and the general oil pump. If the oil is dirty and the filter is clogged, it is necessary to change both.
Defective oil pump... Regardless of its design, it is necessary to check how it works, as well as the effectiveness of the response. In case of malfunctioning, the pump must be dismantled and attempted to be repaired. If this was not done, then this unit must be completely replaced. When you are not able to repair the oil pump yourself, it makes sense to seek help from a car service.
In this vein, it is possible that the oil pump is in good working order, but its technical specifications designed to pump oil with a different viscosity. That is, a situation is possible when the car owner has filled in engine oil of a different viscosity than the one recommended by the automaker. If the lubricating fluid is very thick (more viscous or simply very dirty), then the pump may not be able to cope with its pumping, respectively, the pressure in the system will be less than it should be. This will not only lead to the fact that the oil light on the dashboard will light up, but also to the operation of the pump in extreme mode, which will automatically reduce its resource and expose it to the risk of premature failure.
Oil leaking from the system... If you constantly face the problem of when, then you need to look for the reason where it can go. Each car has a so-called "normal" consumption, which is directly indicated in the documentation. However, if this value is increased too much, a diagnosis must be performed. To do this, you need to inspect the elements fuel system, check the condition of the cylinders and pistons, the condition of the cylinder head gasket and the head itself, see the presence of oil stains on the engine elements, whether the oil is mixed with antifreeze, and so on. Most often, a leak occurs from under various seals and seals. In case you are not able or do not want to do such work, contact the car service for help, the masters will do this work for you.
Significant cylinder / piston wear... It is necessary to assess their condition. First and foremost makes sense in this case. An indirect, but not the only, sign that the cylinders are significantly worn out is the appearance of exhaust pipe... This diagnosis is best performed in a car service using special equipment. In the event that the engine is really in a pre-repair condition, it makes sense to grind the cylinders and perform the so-called "capitalization". This, among other things, will reduce oil consumption, which means that the oil light on the dashboard will no longer bother you.
Punched cylinder head gasket ... This is a very dangerous situation, and if it is identified, it is necessary to carry out renovation worksince driving with a punctured head is very dangerous for the engine, there is a risk that the engine will "knock", that is, fail.
Rare causes of oil light bulb activation
There are a number of other unlikely reasons why the oil light on the dashboard may light up. In particular:
- Faulty wiring and / or vehicle ECU... In the first case, for example, the insulation of individual wires may be damaged, due to which a false signal will be sent to the light bulb through the wiring. However, in most cases, this situation is monitored electronic unit control and it automatically through the lamp Check Engine will notify the driver of such a breakdown (for this you need to have an error scanner of the ELM 327 type). As for the ECU, it may be a banal "glitch", that is, a failure computer program... However, this happens extremely rarely, and it makes sense to check the control unit in the presence of other, more complex, breakdowns. Sometimes on the forums you can find information that the reason may be poor-quality soldering of one or more tracks of the control unit. Accordingly, they need to be re-soldered, but for this it is better to seek help from a car service, where there is the appropriate equipment and qualified personnel.
- The oil filter was not changed during oil change... In particular, this can cause the light bulb to come on after changing the oil. remember, that the filter must be changed when changing the lubricant... If you have driven quite a bit after the appropriate replacement, then you can replace this unit with a new one. If the mileage is already large enough, then it is better to change the oil again and already with the installation of the oil filter. A similar situation can occur if the new oil filter was not tightened tightly enough (you need to observe the value of the moment, and you can find it out in the technical documentation for the car) or be simply defective.
- When starting the engine in very coldy oil light can light up for the first few seconds, and then go out... This is due to the fact that at low temperatures the oil becomes very thick and it is difficult for the oil pump to pump it through the system, respectively, insufficient pressure (and often a vacuum) is created in it, which is perceived by the corresponding sensor as a malfunction. However, after a few seconds / minutes, the oil regains its fluidity and the pressure in the system is normalized, respectively, the sensor detects this, transmits a signal to the ECU, and the light goes out. Please note that you should always choose an oil, not only in accordance with the recommendations of the automaker (usually it allows the use of oils with several similar viscosities), but also with the operating conditions of the machine. In particular, we are talking about low-temperature viscosity. A similar situation can occur after a long parking period without starting the engine (for example, several months), especially if there is old (dirty) oil in the crankcase.
How long can you drive if the oil lamp is on
Also, many car enthusiasts are interested in the question of how much can you drive when the oil light comes on? The answer to it depends on the reason why this situation was caused. From general considerations, we can say that when the lamp lights up, the first thing to do is check the oil level. And if it's lower minimum value, and there is nothing to top up, then with a low level you can drive literally several kilometers with a minimum engine load (that is, with medium engine speeds and at low speed) to the place where you can add / change the oil.
There you need to do additional diagnostics, since activation of the lamp may indicate not only a low oil level, but also other reasons listed above. Do not operate the car with a low (below the minimum required value) oil level in the crankcase. This leads to significant wear and tear and the risk of complete failure of the power unit. Of course, this leads to significant costly repairs!
If there is no oil pressure in the engine, and a red light is on on the instrument panel, the motorist begins to panic a little. It should be noted right away that you cannot drive with this kind of problem, as you can get serious breakdowns after a few kilometers of movement. There is little pleasant in the problem with the oil sensor, since as a result, the motorist can simply get the crankshaft jammed or the dismemberment of this device into several pieces. After that movement vehicle becomes completely impossible. Based on the considerations that the consequences for the wallet and health can be catastrophic, it is necessary to pay attention to the problem in time and try to neutralize it as quickly as possible.
1. Reasons for the lack of oil pressure
If the motorist noticed that the oil pressure lamp on the instrument panel in the car lit up, then it is necessary to "ram" the vehicle into tow and start looking for the cause of the potential danger for the entire car. There are, in general, very few reasons, but none of them can be ignored, since it is she who can eventually become fatal. To the reasons for the lack of oil pressure in the engine internal combustion include: malfunction of the oil pump device, which occurs accidentally or due to wear, poor-quality repair; malfunction of the oil pressure sensor itself, the causes of which are also unique; huge oil leak from the line, as a result of which it can go in and out. In addition, the oil line itself or the filter could be clogged. The most common problem lies in the ordinary low oil level in the reservoir.
2. Problems with the oil pressure sensor
The oil pressure sensor is a light that is a warning that there may be a problem with the system or with the engine. Among the various potential causes of this phenomenon are: poor quality repair power unit, a problem in the operation of the internal combustion engine, the rare performance of the necessary maintenance of the vehicle. Nevertheless, if you figure it out, the very cause of the malfunction will not play a big role, since this will not make it easier for the motorist.
It's important to remember right away important point: If such a problem is found, then it is necessary to make immediate repairs or take certain actions to eliminate this malfunction. First of all, it is necessary to detect the very malfunction of the pressure light bulb lighting in the shortest possible time and carry out quick work to eliminate such a problem.
3. Possible oil leakage from the oil line
It is important to note right away that the leak can be quite small and invisible.It won't be a problem if it happens directly inside the internal combustion engine. The problem will come when it occurs outside, also during movement. The result of this is that the engine is completely oil-free. Most often, a hole may appear in the filter, or the rubber band just squeezed out from under it. As a result, a gradual oil leakage will occur, which is difficult to notice.
In addition, the filter may simply rust, then the leakage will be even stronger, and then you will definitely not get rid of the problems. As a result of wear of the crank mechanism, leakage into the interior of the engine may occur. Such problems include wear of the main bearings, various kinds of bushings camshaft and balancers. An oil pump pressure relief valve that is stuck due to some "unknown" reason will be able to dump a huge part of the oil into the sump. Thus, it can be determined that there are problems that can lead to many negative consequences, in particular - complete failure of the vehicle's internal combustion engine system.
It happens quite rarely, but it does happen. Sometimes filters and oil lines themselves are clogged. This can happen for many reasons, but the main danger lies in the fact that the oil line is simply clogged with debris, carbon deposits, dust or dirt. All this will lead to disruption of stable operation and generally the performance of the entire node. Very often, all spare parts for a vehicle are not stored properly, as a result of which they become clogged with a variety of pathogens of undesirable consequences. After assembling all these elements into one engine, you can get a conglomerate of chaos and a low-quality product that will affect absolutely the whole car system in the most negative way.
It is also important to note that those motorists who allow this kind of undesirable moments decide to remedy the situation by means of ordinary flushing from the outside of the unit, believing that this will solve the problem. However, it is imperative to untwist the oil lines and clean them. And this must be done not only when the rooster bites, but regularly during long-term operation of your car. The same goes for a clogged filter.
If the filter is clogged, the oil pressure will constantly be relieved, which will happen by means of a pressure reducing valve, as a result of which the internal combustion engine will not detect oil in the right place. Why is it clogged? Everything is as easy as shelling pears: you need to use quality parts, quality oil, which, after burning out in the engine, will not leave carbon deposits and deposits everywhere, which will subsequently be washed off with another oil and form solid particles that clog the filter as a result.
However, the most common problem lies in improper care and maintenance of items such as oil pump, filter, etc. The fact is that motorists simply forget to make an ordinary inspection and periodically clean these elements. It should always be remembered that even minimal oil deposits in the future can clog the filter, "break" the oil pump, right down to the engine. Even with ordinary repairs, so what's there, when inspecting the engine, you must always pay increased attention to these details.
Oil dilution occurs very often. This happens when fuel enters the oil. It is important to note that the pressure with such a malfunction will not disappear immediately, it will gradually decrease, and as a result, the oil pressure lamp will just light up at one moment. In any case, by that time the internal combustion engine will already need a major overhaul, whether the motorist wants it or not.
There is an indicator indicating insufficient oil pressure in the engine. If it lights up, this directly indicates that something is wrong with the engine, however, it will not be possible to determine why the sensor has triggered without looking under the hood, since there are several reasons why the oil pressure lamp is on. Only one thing can be said with certainty: it is impossible to start or continue driving a car, since this threatens to damage the power unit.
The oil pressure lamp plays the role of an indicator, signaling, as a rule, about the presence of serious problems in the engine. A pressure sensor located in the lubrication system continuously monitors its value and, if it falls below the permissible level, sends a signal and lights up on the dashboard control lamp.
Why does the sensor work?
The reasons for this can be very different:
- insufficient oil level;
- problems in the lubrication system;
- damage to the engine oil pan;
- poorly executed overhaul power unit or its untimely and improper maintenance.
To determine the cause of the operation, first of all, it is important to note exactly when the oil pressure lamp came on, immediately after starting or while driving, and how exactly it lights up. It blinks or not, if it blinks, then whether it depends on the crankshaft speed, whether it goes out as the engine warms up or as the crankshaft speed rises, etc.
Insufficient oil level
Most probable cause, according to which the oil pressure sensor is triggered, is its insufficient amount in the lubrication system. Therefore, the first thing to do if the oil pressure lamp comes on is to turn off the engine, wait a few minutes so that the entire contents of the oil line flow into the crankcase of the engine, and check its level with a dipstick.
If the level is below normal, the cause has been found. If the warning lamp on the dashboard blinks or goes out with increasing crankshaft speed, this may also indicate an insufficient lubrication level. The next step is to establish why the fall occurred.
A decrease in the amount of lubrication can be observed both in a worn out engine and in a perfectly serviceable one. If the motor is old, you need to carefully examine it for the presence of oily traces of leaks. It will not be superfluous to look under the car: oil stains may remain on the ground. Of course, all leaks must be repaired without delay.
Oil consumption can be a feature of the engine. Many cars, being perfectly serviceable, consume oil. For example, for 2.4-liter Honda engines, a consumption of about 200-300 ml per 1000 km is considered normal, and Mercedes for some of its engines considers an acceptable consumption of up to 1 liter per 1000 km.
The specific consumption depends on the driver's driving style: the higher the crankshaft speed, the higher the lubricant consumption. The car owner should be aware of such features of his car and have a canister in the trunk for refilling.
Poor quality oil filters
The oil pressure lamp may light up due to a poor quality oil filter. In an effort to save money, many car owners purchase non-original filters. After stopping the engine, some oil must remain in the filter, otherwise "oil starvation" may occur. Cheap oil filters of dubious production are not able to retain oil in themselves, and it flows into the crankcase, as a result of which the aforementioned effect occurs.
Defective sensor
The oil pressure indicator may come on if the pressure sensor is faulty. The display system works as follows: the sensor in the engine monitors the oil pressure, when it drops, the sensor closes to ground, and the control lamp lights up, with an increase in pressure, the circuit opens and the lamp goes out. If the sensor is faulty, it can close and open spontaneously, regardless of external factors. 
If the lubricant level is normal, for diagnostics, you can start the engine and raise the speed to 4-5 thousand. If at the same time the control lamp does not go out, it is likely that the sensor is out of order.
Defective pressure reducing valve
A working bypass valve is in the closed position if the pressure in the lubrication system does not exceed the norm. When the engine is started, an indicator on the dashboard lights up until the pressure reaches the nominal value. Within one to two seconds, when the valve is closed, the pressure rises to the operating value, and the indicator goes out. If the oil pressure lamp is on and does not go out, it is likely that the valve is stuck open and the pressure in the lubrication system remains low.
Oil pump problems
Low pressure in the lubrication system may indicate problems with the oil pump. First of all, the oil intake screen may be dirty. Dirt particles and wear products settle on it, gradually clogging it and preventing the free movement of the lubricant. This usually happens if the car owner untimely changes the engine oil. Another reason could be low quality lubricant poured into the motor.
As the engine warms up, the oil dilutes and begins to circulate more freely, as a result, the control lamp goes out. To establish whether this is actually so, you can only dismantle the oil pan.
If the mesh is not dirty, the oil pump itself may be out of order. Despite the fact that he continues to work, he is not able to create the required pressure. Checking its condition will show if it needs repair or replacement.
Damage to the oil pan
This problem is a consequence of the pallet hitting an obstacle. The metal from which it is made is quite brittle, and with a strong impact it easily breaks through. As a result, all the oil is on the road.
The oil pressure lamp is a warning that something is wrong with the engine. The reasons for this phenomenon are problems in the operation of the engine, the lack of proper and regular maintenance of the car, when the repair of the power unit is performed poorly.
In fact, the reason does not play a big role, it is unlikely it will be easier if you find someone who is to blame for this malfunction. The main thing is the problem and it needs to be solved. It is necessary to detect the malfunction for which the pressure light came on, to carry out work to eliminate it, otherwise the consequences can be more complex and much more global.
The main reasons that the sensor reports a malfunction
A low oil pan level is perhaps one of the most common reasons the oil pressure light comes on. With regular vehicle operation, it is necessary to constantly monitor the oil level, as well as the absence of any leaks on the engine housing. Any, even insignificant oil stains at the place of permanent parking of the car should cause you anxiety. However, one must not overlook the fact that a drop in the oil level can also occur in a car that is in perfect working order.
Also, the oil filter can be the cause of the oil pressure light coming on. Usually, this occurs after the next oil change, when a defective or non-working oil filter comes across. If the oil filters bad quality, then they do not implement the function of keeping oil inside the filter and it flows into the car's crankcase without any obstacles. After stopping the engine in oil filter a certain amount of oil should remain. This is necessary so that the effect of "motor oil starvation" is not obtained.
Defective sensor wiring is the reason that the oil pressure light may come on. It is located on the dashboard, it works if something goes wrong with the pressure and depends on the pressure sensor. When the oil pressure is below normal, the sensor closes the lamp to ground. After the pressure rises to the set level, the pressure returns to normal, the sensor contacts open and the lamp goes out. When the sensor is faulty, the lamp will light up when the pressure changes, for example, the lamp will not go out during gas overload.
The oil pressure lamp may also light up when the pressure reducing valve fails. When the oil pressure level in the system is very low, the serviceable pressure relief valve must be in the closed position. In the event of a freeze or jam of the valve in the open position, the required pressure cannot build up in the system, as a result of which the oil pressure light comes on.
The oil pressure lamp is on when the pressure reducing valve fails. When the oil pressure level is very low in the system, a serviceable pressure relief valve must be in the closed position. In the event that the valve freezes or jams in the open position, the required pressure does not form in the system and the oil pressure lamp comes on.
The oil pressure sensor will diagnose the malfunction using warning light, in case of failure of the oil pump. If the oil pump is unable to provide the pressure required for normal lubrication, the contacts of the oil pressure sensor are closed and the oil pressure lamp on the dashboard signals a malfunction. After the oil pressure check is completed, the oil pump can be checked. To do this, you will have to remove the oil pan.
If you cannot find and eliminate the cause yourself, contact a specialist. This will save you time, and some may even have nerves.
