Idle speed regulator VAZ 2115: Replacement and check

As a rule, repair and maintenance of the “tag” can be done with your own hands. Many car owners do this. Sometimes a VAZ 2115 has a problem with the engine idling. And then questions arise: where is the idle speed sensor on the VAZ 2115 and how to check its serviceability? Is it necessary to replace the part?

The idle speed control (or, as it is more commonly called, the idle speed sensor) is located in a mounting hole on the throttle body. The part is a cylinder with two small ears for fastening and a cone-shaped needle at the end.

The function of the idle speed sensor (this applies not only to the VAZ 2115, but to any car) is to regulate engine speed in neutral gear or when switching from one gear to another. The valve located outside the housing regulates the air supply to the combustion chambers. Its task is to open the throttle valve slightly if it is necessary to lean the fuel mixture (add a little air to the fuel). Proper operation of the element contributes to an increase in idle speed.

Important addition: IAC is installed only in VAZ 2115 models equipped with a mechanical throttle unit. In cars from 2010 to 2013, where the gas pedal is electronic, the sensor’s operation is handled by electronics.

Purpose

The idle speed sensor assumes the performance of a rather important function, which is to constantly regulate engine speed while driving in neutral gear, as a result of which you will not have to worry about the normal and uniform movement of the vehicle. This device also controls the speed during the process of switching from one speed to another, which is also quite important, since in the absence of such control, switching may occur unevenly, as a result of which the car will simply stall, which is unacceptable while driving, especially at high speed.

The valve, which is located on the outer part of the housing, is responsible for regulating the air supply to the combustion chambers, as a result of which the throttle valve opens slightly if it is necessary to connect the fuel mixture and air. Only proper operation of the sensor guarantees the ability to increase idle speed.

The important role of a small device in a serious unit

Participating in the general algorithm of operation of the vehicle’s electronic system, the IAC is designed to automatically supply a certain amount of air when the throttle valve (DZ) is closed. Thus, it maintains the set idle speed (ISR) of the engine, preventing it from stalling when the gas pedal is released and the gearshift lever is in neutral position. The operating principle of the UDS is as follows:

• the amount of air entering through the remote control is controlled by a mass (total) air flow sensor - mass air flow sensor;
• receiving information from it, the controller (electronic control unit) regulates the supply of the required amount of fuel to the fuel injectors (Fuel Injection) of the car;
• he, using the data from the crankshaft position sensor (DPKV), controls the IAC in accordance with the required speed;
• automatically sets the speed when the engine warms up.

Having safely got out of the intersection, you need to make sure that this regulator is working. Since it does not have a self-diagnosis system, the VAZ 2114 computer may not generate errors. You will have to check it using a general analysis of engine operation.

Sensor location and design

The idle air control is located in the mounting hole on the throttle body. It is a small cylinder that has two small ears, with the help of which the sensor is directly attached with a cone-shaped needle at the end.

Due to the fact that the sensor is small in size and has a very simplified design, the likelihood of various malfunctions and problems appearing is quite high, and therefore it is important to pay attention to the appearance of the first signs of a malfunction. If problems are observed, it is not recommended to use the vehicle, as the performance of internal structures will deteriorate.

Location of IAC VAZ 2115

Cleanliness of the damper assembly

The throttle valve assembly is diagnosed by visual inspection for contamination. Clean the part with cotton swabs and a toothbrush moistened with a cleaning solution. For ease of work, the device is dismantled. After cleaning, it is recommended to blow out all channels and pipes of the unit with compressed air using a tire inflator.

To clean the part, it must be dismantled

Attention! It is recommended that the channel responsible for removing gases from the crankcase be completely filled with a cleaning solution before purging - the diameter of the element is very small and there is no other way to access it

Video: How to clean the throttle body

Is it possible to diagnose DPKV and DSA?

A breakdown of the DPKV and DSA (Hall sensor) is indicated by the Check Engine indicator that lights up on the car’s dashboard. Testing these devices is only possible using special instruments (oscilloscopes). You can first check the integrity of the wiring; if it is broken, the damage should be repaired.

1. The DPKV sensor is installed on a bracket located in close proximity to the generator drive pulley.
2. The DSA is located on the speedometer drive mechanism of the gearbox.

For a more detailed introduction to methods for detecting faults associated with engine malfunction in idle mode, it is recommended to watch the following video.

Symptoms of a problem

If one of the following symptoms appears while using the car, this indicates a malfunction that will need to be eliminated:

• Some vibration of the engine appears during idling, that is, the vehicle shakes and rattles, and makes strange sounds.
• The machine stops functioning when switching to XX. Switching off can occur at the moment when the gears are changed or when driving in neutral gear.
• When starting the engine in a cold state, there is no increase in speed. If the part is working normally, there is a constant increase in indicators, otherwise they remain in one place, that is, at a fairly low level in comparison.
• There is a sharp increase or decrease in engine speed when idling, which can cause an emergency situation on the road. It is quite easy to notice such changes - sharp fluctuations of the instrument needle occur during movement.

In some cases, such symptoms indicate the presence of other problems, but it is worth noting that in any case it is necessary to check the idle speed sensor, just for your own safety.

Fault marker and cause

Many car owners will say that it is very difficult to calculate the failure of the IAC on a VAZ 2115, since signs of a malfunction do not always indicate problems with the regulator. Moreover, the control unit is often treacherously silent and does not signal the owner with the Check Engine icon. It’s just that the ECU is quite primitive and cannot always determine where exactly the failure occurred. Because of this, drivers are guilty of bad fuel, a clogged filter, low-quality spark plugs, etc. But thanks to the inquisitive owners of the “tags”, the main signs of an IAC malfunction have become known:

• painful starting of the internal combustion engine, especially in winter;
• floating speed when hot, in the range of 850–1100;
• the engine freezes if you switch to neutral and release the gas;
• The firmware reduces the speed to 800–900 on a cold internal combustion engine (less than 40 °C), without waiting for it to fully warm up.

The listed symptoms most likely indicate problems with ICC. There is constant movement inside the sensor, causing natural wear and tear. Often in the lead screw and rotor. Even a small amount of play does not allow the ECU to set the steps correctly, so the fuel mixture is incorrect, causing the engine to operate incorrectly. Sometimes the air valve simply becomes clogged, which also negatively affects the operation of the fuel system.

Examination

To carry out an independent test, you will need a multimeter, which will need to be used in two stages: checking the state of the power circuit and checking the sensor itself.

Checking the power circuit condition:

The sequence of actions during verification is quite simple and understandable:

• The multimeter is turned on and the measurement is configured with a limit of 20 Volts
• Remove the corresponding connector from the sensor and turn on the ignition
• The probes of the device are connected to the connector, and a direction of at least 5 Volts must be shown - then everything is normal

Checking the functionality of the sensor:

In order to check the condition of the sensor, you will need to:

• Switch the multimeter to the device voltage measuring state
• Connect it to the terminals on the idle speed sensor
• Rotate the central part of the sensor, while constantly monitoring the state of the indicators - they should change smoothly

If all conditions are met, then the sensor is operational.

How to check the idle speed sensor on a VAZ 2115?

Some difficulties in servicing the IAC on the VAZ 2115 are that the error codes of this unit are not displayed on the on-board computer display. Unlike, for example, TPS, the data of which is reflected on the on-board vehicle. Therefore, the car owner can only check the serviceability of the idle speed sensor manually. To do this, of course, you need to remember where this sensor is located. You can carry out the test armed with a multimeter and asking an assistant to participate.

First you need to open the hood and disconnect the block that provides power from the sensor. In addition, you will need to move the throttle mount some distance from the IAC.

You should not ignore the condition of the regulator circuit; it is best to check it first. Or the problem may be a faulty or discharged battery. In any case, the multimeter will show exactly where the problems occurred. The verification itself can be carried out using the following steps:

1. Set the multimeter to voltmeter mode.
2. Connect the black probe (minus) to ground, and the red probe (plus) to the outer side terminals of the block (A and D).
3. Now the assistant needs to turn on the ignition, and the inspector needs to look at the voltmeter. The device must show at least 12 volts. If the reading is lower, then the battery or alternator needs checking. If there is no reading at all on the multimeter, this is a signal of a faulty wiring or engine control unit. These are the elements that need to be diagnosed.

If everything is normal in the circuit, you should proceed directly to checking the IAC. You will also need a multimeter, but in ohmmeter mode. Diagnostics is as follows:

1. The multimeter leads are connected to the terminals on the left side of the valve (A and B) and then to the terminals on the right side (C and D). Normally, the reading on the multimeter should be approximately 53 ohms.
2. The probes are connected to terminals A and C, and then to terminals B and D. An infinity symbol should appear on the device.

Other readings on the multimeter indicate a valve failure. There are two options: either replace the faulty part with a new one, or clean it with carburetor cleaner.

Replacement

Replacing the idle air control sensor on a VAZ 2115 is a fairly simple task that does not require much experience in car repairs. To replace, you only need a Phillips screwdriver and nothing else.

Let's start replacing the sensor:

• Remove the connector from the regulator;
• Unscrew the two screws securing the sensor to the remote control housing;
• Using a rotating motion, remove the IAC;

We install the new IAC in reverse order without damaging the O-ring.

Reverse Controller Replacement Guide

How to replace the reverse sensor:

1. First, the car should be driven into a pit or overpass. Raise the parking brake lever and set the gear selector to first speed. This will prevent the machine from possibly rolling away.
2. Next, you need to remove the protective cap from the contacts of the device; you need to disconnect the contacts from the RZH. When dismantling the gearbox regulator, some of the working fluid will come out, so you should place a container to collect the oil under its installation site.
3. After this, you can begin to remove the device. Usually it can be removed by unscrewing it by hand, but sometimes, if the regulator is installed very tightly, it is advisable to use a wrench or socket. The head size should be 22. If the regulator is very stuck to the seat, then it may not be possible to unscrew it with the head. Try spraying the installation area with WD-40 and wait a few minutes. If this does not help, then you will have to use a chisel and hammer to remove it, but be careful not to damage the gearbox housing.
4. After the old RZH is removed, you will need to install a new regulator in its place.
5. If, during replacement, some fluid gets onto the transmission housing, it must be removed using a dry rag. Also clean the location where the regulator is installed, as contamination may cause it to malfunction or become inoperable.
6. Reinstall the connection connector and the protective cap. If, during the replacement, a significant amount of transmission fluid comes out of the gearbox, then lubricant must be added to the box. Please note that the oil must be fresh, and not used oil that came out of the gearbox. If you notice that the drained fluid is too dirty and contains wear products, then it makes sense to think about replacing it.

Photo gallery “Replacing RZH”

WHERE TO FIND IT ON THE ENGINE

If someone does not know where the idle speed sensor is located, then we will tell you about its location. These devices are installed on the throttle bodies, fastened using two screws. There is also such a method of fastening as “landing” on the varnish. But it has not become widespread due to the complexity of such work. In the picture the arrow indicates the place where the pxx is installed on the VAZ 2114.

Do-it-yourself IAC cleaning

How to clean the IAC? The procedure for cleaning the device begins with removing the device, we described this above. Once you have the device in your hands, you first need to clean it with a dry cloth and cleaning fluid, which is usually sold in aerosol form. Alternatively, you can use WD-40. In addition to the controller itself, you should also clean the seat. Press the canister with the product several times, with the aerosol stream directed towards the tip of the IAC, which is also called the needle.

It is best to use carburetor cleaning fluid.

Depending on the design features of the IAC, this needle can be either plastic or metal. Clean the sensor needle directly, since liquid should not be allowed to get under the spring into the inside of the device . If you do hit the spring, the regulator will have to be purged with a large volume of air; for this you can use a pump or compressor. If liquid gets into the device mechanism itself, it can damage the lubricant inside it, and this, in turn, will cause a quick breakdown of the device. Choose the correct dosage of the product and do not dose the liquid too much, as this will also force you to clean the spark plugs in the future.

Checking the serviceability of the sensor

If you notice unstable engine operation at idle, you should not immediately go to the store for a new device. First you need to check the functionality of the node; perhaps the problem does not lie there. To do this, do the following:

1. Turn off the ignition.
2. Disconnect the connector with wires from the sensor.
3. Take a multimeter and check the resistance between pins A and B, C and D.
4. Acceptable resistance values ​​range from 40 to 80 ohms.
5. If you get different indicators at the output, then the regulator is faulty, therefore, this unit needs to be replaced.
6. Is the resistance within normal limits? Then measure the same indicator between pairs of contacts B and C, as well as A and D.
7. The tester will show infinity or open circuit.
8. If there are other indications, the device may be considered faulty.

Using these simple steps, it is easy to determine the functionality of the idle air control on your VAZ-2115. If the element is broken, then proceed to consider the process of replacing the device.

Carburetor internal combustion engines

Here the vast majority of reasons lie in the dosing device itself. The high idle speed in this case is due to:

1. Incorrect minimum setting. The mixture supplied with the carburetor must be adjusted using the appropriate screws.
2. Stuck choke: If it doesn't open all the way, not enough air is getting into the cylinders.
3. First camera shutter. It may not close completely due to a mechanical defect or an incorrectly adjusted actuator.
4. The fuel level in the carburetor float chamber is too high

Ignition system

The reason for the speed fluctuation may be a damaged distributor cap, high-voltage wires or spark plugs. These elements should be checked and replaced if necessary.

Source

OPTIONS FOR TROUBLESHOOTING

It is clear that if any emergency situations arise with the motor, it is advisable to contact a specialized service. However, this procedure is not always possible. Therefore, it is worth knowing how to independently diagnose the main systems and key parts.

THROTTLE VALVE AND ASSEMBLY

When the speed drops at idle and the car stalls, you need to pay close attention to the details of the throttle assembly. Long-term operation of the car on low-quality fuel, untimely maintenance of the air filter can lead to malfunctions of the throttle valve

It periodically jams if debris gets into the equipment.

Throttle valve VAZ 2112

The problem can be solved by cleaning the system. The throttle is cleaned using carburetor cleaners. Using a compressor, you need to blow out the damper under the pressure of compressed air. It is not recommended to touch the screws located inside and on the side. If cleaning does not correct the situation, the device must be replaced. This operation is not particularly difficult.

CRANKCASE FAILURE

There is an oil trap in the crankcase ventilation system of the engine. Its contamination can also lead to interruptions in engine operation. Crankcase gases do not allow the engine to function normally, the speed fluctuates, the internal combustion engine stalls.

SENSORS

If a gasoline car stalls at idle, then one of the sensors is likely to break. In injection cars with an electronic engine control system, the engine usually starts normally, but then it stops working. It's worth checking here:

• Electronic car indicators;
• DRХХ – device that regulates idle speed;
• Air flow meter (air intake in the carburetor);
• Sensor indicating the position of the throttle curtain.

Electronic control unit in VAZ 2114

Interruptions in the operation of any sensors immediately affect the behavior of the electronics - errors appear in the car control unit. The “brains” of the machine receive unreliable information. It is not transmitted correctly to the engine. It starts working with parameters that do not correspond to reality. Self-testing of this device is not possible. You need to contact a professional for service.

Diagnostics of mass air flow sensor

The idle air control device is usually to blame for engine malfunction when the car idles poorly. But you pressed the gas pedal and the engine started. In the latest VAZ modifications, error information appears on the instrument panel.

When diagnosing, you must use a multimeter. If a part is faulty, it is recommended to replace it with a new one. All sensors are reasonably priced. It is better to start checking with parts that have a simpler design. Then gradually move on to complex devices. We must not forget that the problem may lie not only in the sensors themselves. It is also necessary to check the wiring to them and the presence of stable contact.

CARBURETOR

If the VAZ carburetor stalls at idle speed, then the jets may become clogged. Low-quality gasoline, deposits from the gas tank, contain small particles of debris. They can easily disrupt the operation of the fuel injection system. It is worth replacing the filter in front of the carburetor and cleaning the device itself. The dispensing part is cleaned using a cleaning solvent, which is sold in aerosol cans. Another reason is often a prolonged lack of carburetor adjustment.

In a mechanical fuel pump of carburetor cars, the filter mesh may be clogged with dirt. This reduces the performance of the device. Wear of the membrane and its destruction often leads to clogged carburetor channels.

INJECTOR

A situation that often arises is that various Lada models, as well as the VAZ 2110 injector stalls at idle. It is necessary to check the fuel pump strainer for clogging. This is a common problem with injection machines. It is better to immediately replace the part with a working one.

FILTERS PROBLEM

If the VAZ 2112 stalls at idle, then the fuel filter may be dirty. This also applies to other models of the concern. Generally, it is not practical to clean it. The part must be replaced. The same should be done with a dirty air filter. Low throughput leads to the fact that the air-fuel mixture simply floods the spark plugs.

Self-checking will not always lead to a positive result. It is often more practical to identify the cause of unstable operation of the internal combustion engine at a car service center. It will cost more, but specialized diagnostics will prevent more serious damage to the car.

IS THIS DEVICE REPAIRABLE?

There is no need to rush to purchase a new sensor because in some cases it is possible to repair the idle speed sensor. Very often, especially when low-quality fuel is used, or the engine life is close to a major overhaul, coking of the rod with the conical needle in the device body occurs. What do they do in such cases?

Carburetor cleaning fluid can come to the rescue. A cotton swab dipped in this liquid cleans all contacts well. After this, the cone needle rod is cleaned. Usually after these steps it starts working.

If there is a break in the wiring inside the sensor, then in some cases this can be fixed. You need to carefully disassemble the body of the device and carefully inspect its internal contents. A broken connection wire can be corrected if it is possible to solder it to the connection point. If everything works out, then the soldering area needs to be covered with a layer of varnish to protect it from corrosion. If a wire breaks inside the stepper motor winding, it is almost impossible to fix it. In this case, the sensor is simply changed.