Idling regulator: the nuances of work and replacement. How to recognize a faulty pxx How to understand that the idle speed sensor is broken

Regulator idle move(IAC) is one of the main actuators of the engine control system. The stability of idle speed, fuel consumption, situations with sudden engine shutdown depend on its correct operation.

IAC is in working condition almost constantly, therefore its resource is not very large, usually up to 200,000 kilometers. In the practice of repairing car engines, even with a short experience, the failure of the regulator is quite common.

IAC: what it is and how it works

Idling regulators are usually built in two ways:

direct regulation throttle;
regulation of the throttle valve bypass channel.

As an actuator in gasoline engines a stepper motor is usually used. It has advantages over other drives: greater accuracy, lower current consumption, and pulse control capability.

The diagram of air supply through the bypass channel is shown in the figure:

Thus, when the throttle valve is fully closed, the engine speed is maintained due to partial inflow through the bypass (additional or bypass, from bypass - move around) channel.

The shut-off needle of the IAC valve, moving according to the commands of the engine control unit, adjusts the width of the valve clearance, respectively, the flow of air into the engine, on which its speed depends.

For each type of engine, the manufacturer sets the optimum idle speed, which usually ranges from 600 to 1000 rpm.

Regulators of turns direct action on the damper, the angle of the damper closing is directly adjusted, leaving a small gap to maintain the flow into intake manifold air, respectively, ensuring idle speed.

Video about IAC - what it is, the principle of operation and design options:

The control unit usually controls the number of revolutions according to the engine speed signal coming from.

A separate idle sensor, as some motorists mistakenly think, in modern cars no.

Most engine management systems are built in such a way that when the accelerator pedal is pressed and the revs are increased, the IAC drive is disengaged and remained in the last state before acceleration. This reduces the load on the governor drive.

V diesel engines to maintain idle speed, fuel flow control is also used by the bypass type. For this in the fuel pumps high pressure a special electronic control system is used.

Solenoid or rotary valves are used as IAC drives in high-pressure fuel pumps. These actuators use only two levels of bypass opening - "open" or "closed".

In this way, it is difficult to provide an accurate setting of the idle speed. Therefore, the valves are controlled by a pulse width modulated signal. high frequency(PWM modulation). The larger the pulse width, the longer the bypass channel is open during the period, that is, the revolutions increase.

Switching transistors that control valve operation are often installed in an electronic unit on the fuel pump. Diesel fuel flowing through the pump is used to cool them.

If the fuel runs out, the transistors stop cooling efficiently, overheat and fail. The transistors themselves are inexpensive and the work of replacing them is not cheap. That's why driving on the last drop of diesel fuel is not worth it!

IAC malfunction symptoms

The main signs of a malfunction of the idle speed controller are:

"Floating" of the engine idle speed;

increased or decreased engine speed;

spontaneous engine stop when the gearbox is switched to neutral mode;

at the moment of a cold start, the engine runs at increased speeds, resets them as it warms up, the absence of this mode is also a sign of a malfunction of the regulator;

a decrease in the engine speed when an additional load is turned on (stove, headlights, brushes and other powerful consumers).

Where is the regulator and its design

The appearance of the IAC with a bypass system is shown in the photo:

Sectional view:

In some cases, the IAC can be repaired if the winding breaks or the stem is jammed. Disassembly of the regulator should be done with extreme care. In some cases, it can be restored by cleaning.

A typical location for the IAC is directly at the throttle body. Removing regulators is usually straightforward.

How to check the idle speed control

IAC error messages in the form of a message such as "idle speed controller, short circuit or open circuit". Usually, just, the malfunction is an open circuit.

This may be a fault in the winding (open circuit) of the regulator itself or a disruption in electrical communication with the engine control unit. Both options should be checked.

You can check the health of the windings using a multimeter in the resistance measurement mode at the limit of 200 ohms. Resistance of windings in good condition stepper motor usually in the range of 30 to 100 ohms. They are connected to the windings through the idle speed regulator connector according to the electrical diagram.

Video - checking, diagnosing and replacing IAC with Lanos, Chance, Forza, Cherry, Sens:

Highly common reason breakdown of the idle speed regulator - jamming of the stem. Moisture, foreign liquids, dust gets into it, which leads to its corrosion and seizure. In order to check this, a special pulse signal generator is required for forced control of the regulator drive. Such a check is possible only at the service station. In this case, cleaning can help.

Most reliable way performance checks - installing a known good idle speed controller from a similar engine.

How to clean

In order to clean the IAC, it must be dismantled from its original place and disconnected from the connector.

Some specialists immediately resort to cleaning with aggressive WD products. It is not right.

You must first try to wedge the neutral regulator silicone grease... It's okay if it gets inside the regulator. If the lubrication does not help, they sequentially proceed to cleaning with alcohol, solvents, carburetor cleaners, and finally, if all else fails, the most aggressive WD-shki.

Cleaning is carried out by partially soaking the area of the rod-working hole for 10-15 minutes, after which this area can be blown out with a compressor.

In some cases, the cause of a malfunction of the idle speed control system is a clogged bypass channel. It must be cleaned first. Canal cleaning can be done using any suitable means using soft natural fiber brushes.

Replacement

When replacing the IAC, pay attention to the position of the regulator valve stem. In no case should it be significantly advanced. This is possible if, before installing it, connect it to the connector and turn on the ignition. The stem cannot be inserted manually.

If the regulator with an extended stem is installed and tightened the set bolts, the regulator may be damaged (shearing off the worm gear). A regulator with such a malfunction cannot be repaired.

Some vehicles require a calibration procedure after replacing the idle speed control. It is performed using diagnostic devices on special equipment.

"Lada" of the 14th model is a very popular car in Russia. It is an improved version of the nine. In addition to injection injection, v ICE designs there are many sensors. One of these is DHH. This element is necessary to control and create engine idle speed. The idle speed sensor VAZ-2114 is a slightly incorrect name for the element. This is an idle speed regulator. Inside it is an electric motor, as well as a conical needle. This element may periodically fail. Every owner this car should be able to diagnose this sensor. And in today's article, we'll show you how to do it.

The principle of operation of the element

When you turn the key and turn on the ignition, the rod located directly on the idle speed sensor of the VAZ-2114 is fully extended and goes into the hole that is on the throttle pipe. The adjuster then calculates the required number of steps, and the needle returns to its original position. It depends on the type of vehicle firmware. So, for the popular January 5.1, the position is 110 steps on a hot engine, and on the Bosch firmware - 50 steps on a warm engine.

When the unit has reached its operating temperatures, at the time of speed control, the sensor is set at around 40. With an increase or decrease in the number of steps, the air that passes through the hole in the throttle pipe is constantly changing. If the stem extends, then the number of steps increases, and vice versa. The full stroke of the idle speed sensor of the VAZ 2114 model is 250 steps.

On the new regulator, which has not yet been installed on the engine, the distance from the stem to the flange is no more than 23 millimeters. When purchasing a new probe, measure the length of the protruding head. A certain amount of air is supplied to the motor, which is needed for its normal functioning. Due to this, the idle speed is regulated. Then the air is examined by the mass air flow sensor, and according to its amount, the computer supplies the required amount of fuel through the nozzles into the cylinders. With the help of DPKV, the ECU controls the speed of the crankshaft and changes the position of the idle speed controller. This is how the right amount of air is supplied for optimal fuel combustion.

When the power unit is not yet warmed up, the VAZ-2114 idle speed sensor adjusts the air volume so that the mixture is enriched. At the same time, increased revs... So, you can immediately start driving the car without the need for preliminary warming up.

Malfunction symptoms

The on-board computer installed in the car has very limited functionality and is not able to inform the driver about a malfunction of the idle speed sensor on the VAZ-2114. The computer, like the regulator, is not equipped with a system self diagnosis... But there are symptoms that suggest that the IAC is out of order.

One of the most obvious signs that the sensor is not working properly is the uneven idling of the power unit. A particularly striking symptom is that the engine stops when the driver removes the car from gear while driving.

The characteristic signs of a malfunction of the idle speed sensor on the VAZ-2114 are low revs after starting the power unit "cold". But all these signs are completely identical to those that happen when the TPS fails. This complicates the diagnosis. But how not to get confused? This is checked as follows - in the case of DXH on dashboard the "Check engine" lamp will come on.

How to check the regulator?

If these signs appear, the idle speed sensor VAZ-2114 needs to be checked. The part is disconnected from the block. Then you need to make sure that the voltage required for its operation is supplied to the regulator. You can perform this operation using a multimeter. The check is performed as follows. You need to turn off the car ignition and then measure the voltage. If it is not, then the entire circuit is checked (including the computer). If there is voltage, and its level is about 12 V, then the sensor is working properly. Most likely, the battery is dead. After this check, the ignition is turned on, and the DXX is connected to the block. The idle speed sensor of the injector VAZ-2114 is faulty if at the same time its needle does not move.

Dismantling

If, after diagnostics, it turns out that the reason is in the sensor, then it must be dismantled and replaced. This element on VAZ cars is small in size. It is on the throttle, in seat... Dismantling is very easy. Knowing where the idle sensor on the VAZ-2114 is located (the location of the element is shown in the photo below), you need to unscrew two screws. Sometimes, on rare occasions, it may be necessary to remove the throttle.

Dismantling is carried out as follows. First of all, the car is put on parking brake... Then disconnect the negative terminal of the battery. Next, disconnect the block from the regulator. Be sure to clean the place where the sensor connects to the throttle body. This is to prevent dirt and rust from getting into the hole. Then unscrew the screws holding the sensor.

Cleaning

Any non-working IACs are recommended to be thoroughly cleaned first. This will allow you to finally verify the malfunction. This procedure is very simple and does not require much time from the car owner. For work, a carburetor cleaner, as well as a VD-40 universal tool, will come in handy.

Cleaning is performed as follows. The block is removed from the regulator. Next, one of the cleaners is applied to a cotton swab. Then the contacts are carefully processed with a stick. After that, you can unscrew the screws that hold the regulator and remove it from the seat.

When the sensor is installed in its place, it is important to measure the distance between the body and the IAC needle as accurately as possible. On a normally operating sensor, this gap should be 23 millimeters. If the sensor does not work after such cleaning, then we can talk about the wear of the guiding needle or about an internal breakage. In these cases, repair is impossible, and the problem can only be solved by replacing the element.

High-quality sensors on the VAZ

Experienced motorists recommend purchasing IACs manufactured by the Omega group. Products from KZTA also receive good reviews. You can buy a regulator in any spare parts store, and the price will be about 350 rubles. When buying, it is worth checking that the store does not offer a fake.

Conclusion

The IAC is a small device that can cause serious problems for the driver. It is not difficult to diagnose and clean this element, and the replacement process will require a minimum of tools. All work can be easily done with your own hands.

Despite the fact that the signs IAC faults are similar to breakdowns of many other elements of an injection internal combustion engine, some symptoms directly indicate a malfunction of the idle speed sensor. Consider how to diagnose yourself and determine faulty regulator.

Breakage signs

IAC malfunction symptoms:

Role in engine performance

To correctly recognize a breakdown of the regulator, you need to understand how the IAC works. We have already considered in detail and a brief diagnostic process, so now we will focus only on the role in the engine's operation.

In the life support system of the internal combustion engine, the idle speed sensor is used to regulate the supply of air passing by the throttle valve (via the bypass channel, the beginning of which is located in front of the throttle valve). When many consumers of electricity are turned on at once, the load on the generator increases and, as a result, on the motor itself. To maintain a stable idle speed and battery charging voltage, the IAC opens the channel, skipping more air in the internal combustion engine. In the same way, increased speed is realized when the internal combustion engine is warming up.

Breakage

The main malfunctions of the idle speed controller:

power failure, which can be caused by problems with electrical wiring, oxidation of contacts in the connectors. With an unreliable connection, such a malfunction manifests itself periodically, which can complicate the diagnostic process;
incorrect stroke of the stem due to contamination;
breakdown of the electric motor;
destruction of the sealing ring;
rod wear. The movement of the shutter of a working IAC occurs without biting, and there should also be no slippage in the worm gear. To assess the condition of the rod and worm gear, we recommend looking at how to disassemble the IAC.

Among the above malfunctions, contamination of the stem is the most common failure. During operation, mud deposits accumulate in the channels of the throttle unit. If your car has not been cleaned with the throttle valve for a long time, most likely problems with idling are related to carbon deposits on the regulator stem. To check the IAC, it is necessary to remove it from the throttle assembly. Carburetor cleaner can be used as a flush.

We recommend not to allow critical contamination of the regulator stem, since the increased load on the electric motor can damage the elements of the IAC control system. There were cases of failure of the resistor electronic unit control unit (ECU) due to current overload of the regulation channel. Most likely, the increased load was provoked by the resistance of mud deposits and carbon deposits to the movement of the rod. The cost of a new resistor is ridiculous, but the prompt determination of this type of malfunction requires diagnostic equipment, as well as the qualifications of the master.

Diagnostics

There are three types of idle speed stabilization systems:

solenoid (there are only 2 contacts in the connector);
rotary (3 contacts in the connector);
stepping (4 pins in the connector).

V modern automotive industry the most commonly used is a stepper motor. At the heart of such a device is a ring magnet and 4 windings located at right angles to each other. Applying voltage to certain windings provokes a rotational movement of the rotor, which moves the rod (shutter) through the worm gear. To determine the working IAC, you need to check the condition of the motor windings. To do this, you need to measure the resistance on the first two contacts and on the second two. To measure, you need the basic ones, as well as the device itself.

Options:

on conclusions A, B and C, D must have a resistance of 40 to 80 ohms. The absence of resistance will indicate an open circuit (for a VAZ, the value is usually 50-53 ohms);
at the terminals A and C, A and D, B and C, B and D there must be an infinitely large resistance, which will indicate the absence of a short circuit. A breakdown of this kind requires the purchase of a new IAC.

To determine if the power wires are broken, you need to "ring" the wiring with a multimeter in resistance measurement mode.

Check engine

Modern injection engine management systems are capable of registering some malfunctions of the idle sensor. For example, consider the recorded deviations indicated in the error mask (a list of faults in which the Check engine) of the engine control unit VAZ M7.9.7 under the EURO III toxicity standards:

P1509 - overload of the IAC control circuit;
P1513 - IAC control circuit, short to ground;
P1514 - IAC control circuit, open or short to +12 V.

Also, when decoding, the error code may appear as "IAC problem". In this case, you should not buy a new regulator right away, as the problem may be in the power wires.

You can read error codes through the diagnostic connector using a special scanner. Decryption of codes can be easily found on the Web. In most cases, a thorough cleaning will help delay replacement. The most accurate and quickest way to identify a faulty idle speed regulator is by monitoring its operation in real time. This will require an oscilloscope, as well as the skills of a diagnostician. It will not work to apply voltage to the sensor terminals to watch the movement of the rod. The IAC is controlled by Pulse Width Modulation (PWM). There are special devices on sale for quick check IAC of VAZ cars. But their cost is too high if we talk about the frequency of use when repairing a personal car. On the forums of radio amateurs, you can find testers made by yourself.

The car engine is completely closed. However, the motor continues to run and maintains a constant speed, thus eliminating the need to restart it at each stop. The main credit for this belongs to the idle speed regulator, which allows sufficient air to be supplied to the intake tract. The breakdown of this small part can significantly complicate the use of the car, so every driver should know how the idle speed regulator works, where it can be found and what the main malfunctions are. If you are repairing a car yourself, it will be very useful for you to learn about ways to restore the regulator and eliminate the unpleasant consequences of a breakdown.

Operating principle

The idle speed control, or, as it is often called, the XX sensor, is a small piece that fits in the palm of an adult. It consists of three main parts - a tapered needle designed to change bandwidth branch pipe, springs, as well as a stepping motor with a rod.

This device allows you to change the cross-section of the bore, which is responsible for the flow of air to the engine when the throttle valve is closed. After turning on the ignition, the sensor automatically extends the stem until the needle enters the calibration hole. When the engine is started, the idle speed control automatically opens the passage, allowing the engine to receive enough air for stable operation. If the temperature is very low, the regulator can supply more air, allowing the engine to speed up for faster warm-up. Thanks to this, the car can also start immediately, without first warming up the engine, without risking stalling.

The regulator is always located near the throttle position sensor - you can recognize it by the characteristic plastic cover of the electric motor, which protrudes strongly above the surface of the assembly. A wire stretches to it, which can be connected to a connector nearby or branch off from a common harness connected to the control unit. Be careful as on new machines the governor is often located under a common shroud to protect the throttle assembly.

Malfunctions

The main sign that you need to pay attention to the idle speed control is erratic rpm when there is no load on the engine. They can fluctuate significantly due to the incorrect volume of air supplied to the intake tract. Most motors react to this problem. increased consumption fuel and strong vibration, which leads to accelerated wear of supports, pillows and some other components. If, with unstable operation at low speeds, be sure that the XX sensor needs an urgent replacement.

It is worthwhile to be wary also in the case when, during a cold start of the engine, there is no significant increase in speed, which makes it possible to accelerate the warm-up. Most likely, the sensor cannot take the calibration position, which makes it impossible to accurately select the required cross-section of the bore. You should take care of the repair of the part even if, at the slightest additional load, for example, turning on the headlights or the heater, the speed drops until the engine stops. In theory, these idle speed control faults do not interfere with vehicle use, but they can cause many problems for the driver.

In the event of a complete failure of a part, the car simply will not start without pressing the gas - given that most manufacturers do not recommend starting the engine in this way, this can become a rather serious problem. In addition, the engine will stall when shifting gears without overthrowing and any other reduction in revs. It should be noted that malfunctions of the idle speed regulator lead to accelerated wear of the engine and fuel system, as well as an increase in the volume of deposits in power unit... Therefore, repairs must be carried out in as soon as possible- this will save a considerable amount of money.

Owners of cars produced by AvtoVAZ definitely need to know how to check the idle speed control, since its breakdown does not lead to the operation of the indicator "". Therefore, the owners of domestic equipment very often recheck many other components, including the intake system, and only then move on to the XX sensor, although it is with it that they should start. Drivers of foreign cars and VAZs last generation such a problem does not threaten - a malfunction of the idle speed controller is displayed on the dashboard and is easily identified by a special scanner.

Diagnostics and repair

It is quite easy to check this part, but sometimes problems arise with its dismantling. Typically, the idle speed control is attached to the throttle assembly with screws, making it easy to remove using a screwdriver. However, in some cars, the XX sensor is fixed with varnish, which causes problems. It is impossible to remove the idle speed control using force, as you can damage part of the intake system of the car. You will have to dismantle the entire throttle assembly, and only then carefully disconnect the sensor.

After determining where the regulator is located and removing it from the engine, check the electric motor. To do this, you need an ordinary multimeter, which needs to measure the resistance of the windings. Contacts are required to be installed in series on windings A and B, and then on C and D, respectively - the resulting figure should be in the range of 40-80 ohms. If you rearrange the multimeter contacts in a different order, the device should show an open circuit - this will be evidence correct work idle speed regulator. Some experts advise you to make a 6 V switch yourself, which will diagnose the work of the part - but will it be useful to you in the future?

In most cases, the cause of the malfunction is a strong contamination of the idle speed regulator - in this case, you need to clean it using the following sequence of actions:

Disconnect the wires and remove the screws. If the XX sensor is fixed with varnish, dismantle the entire throttle assembly;
Soak a cotton swab in alcohol or a special tool and gently wipe the contacts;
If the taper needle, stem, or spring is heavily contaminated, use WD-40 Scale Remover;
Check the condition of the throttle valve and, if necessary, clean it;
Reinstall the regulator and check that it works.

Broken wires may well be the cause of the regulator's malfunction - in this case, you need to clean the contact pads, solder them, and then varnish this place in order to exclude the reliability of the node. Unfortunately, not all failures of the idle speed regulator can be solved by simple cleaning. For example, taper needle wear, stem wear, and motor failure require complete replacement sensor. However, you should not be very upset, since the price of the part is in the range of 500-1000 rubles.

Big problems from small details

The idle speed control is small and almost always invisible in the engine compartment at first glance. However, this device does a very important job of stabilizing the operation of the motor in the absence of a load. Its breakdown can cause quite serious troubles - driving a car will be very difficult and the driver will have to constantly hold high revs... Cars with automatic and robotic transmissions will have to be delivered to the service center by a tow truck. Therefore, at the first symptoms of a malfunction of this part, engage in diagnostics and repair.

In a simplified form, the idle speed controller allows the engine to operate when starting and subsequent stops of the car, for example, at intersections. It supplies the missing amount of air to the fuel mixture of the injector for normal work cold engine or when the machine stops without turning off the engine.

Purpose of the IAC regulator

The idle speed regulator is used exclusively in electronic ignition systems:

proportions fuel mixture in the injector is an on-board computer;
the amount of gasoline or diesel fuel for each cylinder is measured by the ECU;
sensors DPKV (crankshaft), DPDZ (throttle valve), DMRV (air), DD (detonation) are installed in the electronic ignition, according to the signals of which it is triggered fuel pump and the ignition is distributed to specific cylinders;
when the gas pedal is released, the fuel flap is completely closed, the proportions of the fuel mixture are violated, the combustion products are sucked back into the combustion chamber due to the pressure difference in the intake and exhaust manifolds.

Based on the results of the air sensor signals, the controller makes a decision on additional enrichment of the fuel mixture with air, ignoring the readings of the throttle valve sensor at this moment.

The chip on the IAC transmits a signal from the ECU, a bypass channel opens in the idle speed controller, through which air passes in the injector or additional fuel in the diesel engine. Engine speed is leveled, piston and crankshaft wear is reduced.

Operating principle

V carburetor motors the problem of mixture enrichment when starting the internal combustion engine solved the starting handle and adjusting washers. With the emergence electronic ignition this is done by the idle speed regulator in conjunction with the rest of the sensors and the ECU. Its working principle is as follows:

IAC calibration is performed by the ECU controller automatically after detecting this sensor in the system;
in fact, the IAC is a stepper motor with a tapered needle in a special hole in the throttle bypass channel;
The IAC contact does not transmit any signals to the "brain" of the machine, but receives them from the controller, therefore it is not a sensor, but an actuator - an electrovalve;
in turn, the on-board computer “sees” that there is not enough air in the fuel mixture according to the DMRV signals, compared with the DPDZ signals;
voltage is applied to the XX regulator, the needle leaves the channel, the missing amount of air enters the mixture for mixing.

In addition, the ECU receives signals about the temperature of the coolant and oil in the system. When starting in the cold season, it is necessary to warm up the engine to working temperature, in order to reduce the wear of friction parts, therefore the IAC channel is slightly opened to enrich the mixture to the injector, even without the driver pressing the accelerator pedal.

At the moment of start, the operation algorithm is as follows:

the key turns, the ignition turns on;
the stem extends until it stops, the needle closes the bypass channel;
at the moment the rod rests against the calibration hole, the computer counts the steps back;
voltage is applied to the windings, the valve returns to the open position.

The number of reverse steps is programmed in the device firmware. For example, for Basch modifications on a heated internal combustion engine, it is 50 steps, January - 120 steps, respectively. In total, the stroke of the rod is divided into 250 steps, the further it stretches out of the windings of the stepper motor, the more steps the ECU will count. When buying a new IAC, the distance from the landing flange to the stem needle should be exactly 23 mm.

Injector

For work injection engine pure gasoline is not suitable, therefore, a throttle valve with an individual sensor for its position at each moment of time is installed at the collector inlet. When starting the engine or stopping the machine with the engine running, the following occurs:

the computer receives information about the revolutions of the engine shaft;
analyzes how the motor works, that is, clarifies the intended purpose;
then the readings of the throttle position sensor and air are compared, that is, the controller "understands" that the damper is closed, and a lean mixture enters the cylinders;
the IAC valve opens, air is supplied bypassing the damper to maintain the speed at the programmed level

In fact, several devices of the electronic ignition system are involved in the process. If the machine stalls or symptoms of other malfunctions are present, diagnostics are performed manually, since feedback(self-diagnosis) this device does not have.

V diesel engine There is no throttle valve, the idle speed control is useless, other methods of adjusting low speed are used.

Design features

At the stage of the emergence of DCH, solenoid and rotary idle speed sensors were used. They had two positions by analogy with the valve - Open / Closed, which reduced the efficiency of the engine speed control. They have now been replaced by a 4-step valve with step bypass flow control.

If you disassemble the IAC, you can see that it is assembled from four parts:

stepper motor;
four-position stem;
spring;
needle.

When voltage is applied to one of the four windings, the coil is magnetized, interacts with the magnetic ring, moves the stem to one of four positions. Accordingly, the number of breakdowns of this electrical appliance is as limited as possible:

the bypass channel is clogged;
the windings burn out;
the needle or spring breaks.

The sensor is positioned by manufacturers as a "consumable", that is, it is considered conditionally not maintainable. It is cheaper to replace the whole one than to disassemble and repair individual parts. If they are not on sale, you need to grind them yourself.

However, the first reason can be eliminated on our own - with the connector disconnected, we remove the regulator in order to clean the bypass channel with WD-40 universal spray.

Place of installation

Knowing the principle of operation of the IAC, it is very simple to determine where the valve is located - near the throttle valve and its spatial position sensor TPS.

It is extremely rare that the sensor is glued to the valve body for varnish; in other cases, the device is fixed with two screws for which there are mounting holes. The main task of how to adjust the valve with your own hands when installing the IAC is precisely to ensure a distance of 23 mm from the needle to the landing flange.

Read the markings before removing the regulator for replacement. PXX marked 01/03 or 02/04 are considered interchangeable. If you put 02 instead of 01 or 03, the device will not work correctly.

A single harness of four wires from the ECU comes to the idle speed control. Below is a diagram of the distribution for the windings of the electric motor.

The main problem is diagnosing the sensor on our own. It will not work just to apply a voltage to check its functionality to its terminals, since the ECU does it impulsively. The windings burn very rarely, they are more common mechanical faults e.g. bent stem or blocked bypass passage

In the service station, the sensor is checked at stands capable of reproducing an ECU impulse. Even having a multimeter, a motorist can only make sure that the windings are intact and that there is no short circuit between them, nothing more.

Signs of failure

The main symptoms that the idle speed sensor is not working correctly are:

idle speed is unstable;
a decrease in the crankshaft rotation speed when any consumer is turned on (windshield wipers, headlights, air conditioner, radio tape recorder, heater);
no increase in the speed of rotation of the shaft when starting the internal combustion engine;
stopping the engine when turning off the gear or changing gears.

Attention: The indicated symptoms are not the cause of the failure of the IAC by 100%, since they are similar to the failure of the TPS damper sensor. However, in the latter version, the Check error, and the idle speed regulator is not connected with the engine control system, it has no self-diagnosis.

Diagnostics of the IAC

Ideally, regulator diagnostics should be carried out on a stand that can reproduce the pulses of the on-board computer. In practice, this is expensive, and budgetary verification methods are used. In any case, the algorithm of actions at the initial stage is the same:

the handbrake is tightened, recoil devices - shoes are installed under the wheels;
disconnect the "-" terminal from the battery;
knowing where are TPS sensors and DMRV, the location of the IAC is determined;
the valve is disconnected from the on-board computer (the plug is pulled out of the connector).

Further steps are different for different verification methods.

Manual check

The simplest method how to check the IAC in electronic system intake distribution, is manual diagnostics (an assistant is required):

the IAC plug is disconnected from the connector;
two screws are unscrewed, the device is dismantled;
the regulator is reconnected to the ECU, but remains in the hands of the master;
the assistant starts the engine, the rod at this time should be drawn into the coils completely, then, having received an impulse from the computer, move forward a certain distance.

In other words, the operability of the stem is checked, the owner makes sure that this part is not bent, does not wedge inside the valve. However, this does not give 100% guarantees that this modification of the IAC fully complies with the firmware of the controller ECU. The needle extends, but an unknown amount. In the first case, the connector is checked, in the second - the plug, the marking is only on the plug.

In the classic version of the check "from simple to complex", this stage is the initial one, then you should check the integrity of the wires and coils, the condition of the bypass channel, and the wear of the needle. Only after these steps can you assemble a home-made stand with a pulsed voltage supply for complex diagnostics of the IAC.

Diagnostics with a multimeter

At this stage, you will need an IAC tester, which is checked by this device in two modes:

ohmmeter - when the multimeter probes close the contacts C - D and A - B, the resistance should be 40 - 80 Ohm, D - C and A - D equal to infinity;
voltmeter - when the ignition is turned on, the voltage reaches 12 - 20 V.

Attention: the IAC is configured automatically. on-board computer after each connection of the plug of the device to the socket. After dismantling, it is recommended to lubricate the bypass channel with WD-40 spray to clean it. This measure is preventive, even in the absence of contamination of the bypass channel, in the rupture of which the regulator is located.

Pulse check on a homemade stand

Since the stand costs 1,500 - 1,800 rubles, and the regulator costs 300 - 500 rubles, the purchase of the device is not economically profitable for an ordinary user. Simple circuit without microchips is shown below:

it uses 6 V charging from any mobile device;
plug strips are commercially available;
first you need to disconnect the IAC from the on-board controller, then the stroke is checked;
the bright glow of the lamp on the diagram indicates a malfunction of the rod itself;
if the lamp is lit in the incandescent floor, the unit is considered to be in good working order.

The use of a cleaning agent will allow the stem to work again, but only in case of blockages. If this part is bent, the whole regulator must be replaced.

Major malfunctions

The above symptoms of malfunction usually occur in the following cases:

the bypass channel of the throttle valve is clogged with dirt;
the integrity of the wires or coils is broken;
ECU firmware does not correspond to IAC modification.

Checking with the above methods reveals all the causes of the problem. Whenever the regulator or throttle assembly is disassembled, it is recommended to clean the IAC with special fluids / sprays.

Cleaning the needle and bypass

To provide access to the valve parts, the IAC must be removed using the following technology:

disconnecting the shoe from the connector;
cleaning the connector and plug contacts with a cotton swab moistened with WD-40;
unscrewing the screws with a curly screwdriver;
removing the regulator to check the status.

Attention: It is not necessary to disassemble the regulator, it is enough to spray the spring and the stem with the needle with WD-40 spray, wait until it dries, while cleaning the bypass channel of the throttle.

Adjustment is made by the controller itself on-board network... However, for stable engine operation, the distance from the seating flange to the protruding taper of the needle should be checked. By default, it should be 23 mm.

Nuances of choosing an idle speed sensor

The original idle speed sensor is marked as XX-XXXXXXX-XX. The last two digits indicate the compatibility label:

odd (01 and 03) are interchangeable, even (02 and 04) are also interchangeable;
these groups are not interchangeable with each other, that is, instead of the "native" 02 it is impossible to operate valve 01 or 03.

Even in the original regulators, it will not hurt to additionally lubricate the IAC with a mixture of lithol and WD-40 (spring and stem). Since the replacement of IAC with their own hands is in demand by motorists, there are counterfeit regulators that can be identified by the following signs:

there are no distinctive marks on the packaging;
yellow sticker on the case without a frame;
the tip of the needle is dark;
a thin black o-ring instead of a thick red seal;
body rivets do not have 3 mm diameter heads;
a white spring instead of a black product with frequent winding;
the body is shorter by 1 mm.