How to check pxx with a multimeter

How to check the idle speed sensor. Malfunctions, replacement, checking IAC with a multimeter, calibration; where is the regulator located

The idle speed regulator is designed to ensure stable engine operation at idle speed. Controls the operation of the IAC ECU, which, depending on the operating loads, supplies power to the bipolar stepper motor of the controller. Let's look at how to check the idle speed sensor and how to understand that the reason for the floating speed is a malfunction of the regulator.

Signs of breakdown

• Unstable idle (floating speed).
• Spontaneous increase or decrease in engine idle speed.
• The car stalls when you let off the gas.
• After starting a cold engine, there are no warm-up speeds. Regardless of the throttle position, to reduce the ECU catalyst warm-up time by 200-300 rpm. raises idle speed. If the IAC is faulty, the stepper motor will not be able to adequately shift the position of the rod with the conical needle, thereby increasing the flow area of ​​the bypass channel of the throttle assembly.
• When powerful current consumers are turned on, the speed drops or begins to float. Turning on the air conditioning compressor, cooling fan, or combination of electrical devices that load the generator increases the load on the engine, which leads to a drop in the number of revolutions. Therefore, in idle mode, the ECU, using a regulator, increases the flow area of ​​the bypass channel, thereby equalizing the speed.

Malfunctions

• Contamination of mechanical elements that prevents normal movement of the rod. Dust particles penetrating through the air filter are mixed with oil vapors and exhaust gases from the crankcase ventilation system, which over time leads to contamination of the throttle valve elements. Carbon deposits not only clog the bypass channel, reducing its cross-section, but also get inside the idle speed sensor. In this case, the rod begins to move with wedging, which leads to unstable engine operation.
• Wear of the worm-anchor mechanism drive. To convert the rotational movement of the electric motor rotor into translational movement of the conical rod, a worm-anchor gear is used. Worn threads of the worm mechanism will make it impossible for the idle speed sensor rod to move normally.
• Control circuit malfunction. We are talking about breaks in electrical wiring, short circuits due to insulation chafing, and the formation of oxides at the terminals of the wire blocks.
• Electric motor failure. The stepper motor itself is an extremely reliable mechanism, but due to problems in the power circuit, the winding may burn out. If you know how to use a multimeter, then you can check the winding for an open circuit using a universal meter.
• Destruction of the sealing ring, resulting in the leakage of unaccounted air mass flow sensor.

Computer diagnostics

Despite the fact that the IAC is commonly called a sensor, the device is exclusively an actuator that does not have feedback from the ECU.

In other words, the motor control unit sets the desired rod extension by applying voltage to the stepper motor. But the ECU cannot objectively check the actual position of the rod, so the discrepancy between the desired and actual values ​​is not recorded anywhere.

This means that if the sensor malfunctions, the Check Engine light on the dashboard will not light up.

The self-diagnosis system can register only a few faults in the IAC control circuit. Options for errors that can be determined with a diagnostic tool via the OBD II connector before checking the idle air sensor:

• P0505 – error code indicates a malfunction in the control circuit;
• P0506 – sensor blocked, low idle speed;
• P1509 – IAC control circuit overload;
• P1513 – sensor control circuit short to ground;
• P1514 – open or short to +12V IAC control circuit.

Checking IAC with a multimeter

How to check the idle speed sensor with a multimeter:

• In DC measurement mode, measure the voltage at the regulator connector (ignition must be on). Lack of power will indicate a break in the control circuit;
• check the resistance of the stator windings in resistance measurement mode (range - up to 200 Ohms). The SD has two windings, so you need to ensure that the tester terminals are connected correctly. In the technical documentation for the sensor installed on your car, you can find the nominal winding resistance. For example, for РХХ 2112-1148300-02 the normal resistance is 51±2 Ohms, and for РХХ 2112-1148300-01 – 53±5 Ohms (both devices are installed on many VAZ models). If the multimeter readings indicate a resistance approaching infinity, it means that there is an open circuit in the winding circuit. Connection diagram for IAC VAZ 2110

It is possible to fully check the IAC only with the help of special diagnostic equipment. But in most cases, checking with a multimeter, visual inspection and troubleshooting after disassembly allows you to fairly accurately diagnose the presence of a malfunction.

Source: http://AutoLirika.ru/remont/kak-proverit-datchik-holostogo-hoda.html

Checking the idle speed sensor on a VAZ-2110: signs of malfunction

Any injection engine is very sensitive to the performance of electronics and sensors. It is enough for the most seemingly insignificant component to fail, and the engine’s operating mode is disrupted, power drops, and fuel consumption increases. One of such elements on VAZ-2110 engines is the idle speed sensor. Let's figure it out together today how to check, replace, select it.

Idle speed sensor for VAZ-2110

Idle speed regulator.

First, let's decide on the catalog number and price of the unit. An idle speed sensor with the original catalog number 2112-1148300 . Its price for 2018 is about 500-550 rubles, depending on the greed of the seller.

Be careful not to confuse the sensor we need from below.

How does it work and how does it not work?

Idle speed sensor disassembled.

The device is not too complicated. It consists of a stepper electric motor, a calibrated spring-loaded cone and a rod. Installed in the intake manifold after the throttle valve . It is this regulator that is responsible for the smooth and smooth operation of the engine at idle speed.

Sensor on the throttle assembly.

Simply put, the idle air control sensor is a simple valve or actuator that controls the air supply when the throttle is closed, according to commands from the electronic engine control unit. When starting the engine in cold weather, the ECU opens the idle speed control slightly and supplies more fuel to the combustion chamber, increasing the speed to speed up the engine warm-up.

Principle of operation.

Once the engine warms up to operating temperature, the stepper motor moves the conical valve stem forward and reduces the amount of air consumed, thereby reducing the speed. This is how the sensor works.

Signs of sensor malfunction

But it does not work in cases where:

• the engine does not hold idle, the speed fluctuates;
• the engine stalls at idle and when driving in neutral with the throttle closed;
• a cold engine does not start without an open throttle, that is, until we press the gas pedal, the engine will not start;
• low and unstable idle when the engine warms up.

In this case, the Check Engine lamp will not light up . If it lights up, then we look for the cause in the throttle position sensor. In the case where the symptoms are present, but the lamp does not light, the cause should be sought in our sensor. Therefore, now we will check its functionality.

Checking the sensor yourself

To dismantle the IAC, you need to disconnect the block and unscrew two screws.

Before dismantling, you need to thoroughly clean the place of its attachment from dust and dirt and remove the negative terminal from the battery. But first, a check.

Sensor connection diagram.

We look at the connection diagram and check the sensor using a conventional multimeter in the following sequence:

1. Checking for power supply to the sensor. To do this, measure the voltage at the two outer contacts of the block, A and D. Turn on the ignition, place the black probe of the multimeter on the engine ground, and the positive probe on the contacts one by one. The voltage should be within 12 Volts. If it is less or absent altogether, we look for an open circuit or blame the electronic control unit for everything. But first, we check the voltage at the terminals from ECU 4 and 54. Here, naturally, there should also be 12 V.

   The voltage is normal.

2. We switch the multimeter to ohmmeter mode and measure the resistance between contacts A-B and C-D on the sensor itself . As can be seen from the diagram, we are checking the resistance of the winding of the stepper motor of the regulator. Between the indicated contacts, the nominal resistance is from 40 to 80 Ohms, according to the factory rating - 53 Ohms.
3. We check the electric motor for short circuit of the windings . To do this, measure the resistance at terminals A-D and B-C. The resistance should tend to infinity, that is, there should be no contact between the two windings. If there is resistance, no matter what the value, we conclude that the windings are short-circuited. This cannot be cured; we replace the sensor with a new one.

It cannot be said that this testing method 100% guarantees the functionality of the sensor; we only checked its electrical part. The mobility of the cone valve and the magnitude of its stroke are of great importance. And this can only be checked either at a special stand or with a special tester.

Checking the operation of the mechanical part of the sensor

To check, remove the sensor from the throttle assembly.

However, if the electrical part is in order, you can check the mechanical part of the regulator by eye:

1. Unscrew the sensor and remove it from the throttle body.
2. We connect the contact block to the sensor.
3. Turn on the ignition. When turned on, the valve should move forward. If this does not happen, the rod is coked or the stepper motor is not working properly.
4. We measure the distance between the sensor body and the conical valve - nominal 24 mm.

   We measure the distance with a caliper.

If we removed the sensor from the car and the electrical test passed, but we still did not achieve mobility of the cone valve, we try to clean the regulator using a soft swab, a cotton swab and WD-40 penetrating lubricant or an aerosol carburetor cleaner. Good luck to everyone and stable idle speed in any weather!

Soak the valve in cleaner.

Video on how to check IAC

Source: http://carfrance.ru/priznaki-neispravnosti-datchika-xolostogo-xoda-na-vaz-2110/

How to check the idle air control on a VAZ 2114

When the idle speed of a VAZ 2114 becomes unstable, it urgently needs to check the idle speed sensor. What does unstable mean? We answer:

• on the road the engine stalls when changing gears;
• The engine speed then drops sharply, then increases again.

If such malfunctions occur, the IAC is most likely faulty. However, before checking the idle air control for malfunction, let's figure out what it is.

What does it look like and where is its location?

The sensor, or regulator, abbreviated DXX and IAC, regulates the idle speed of the VAZ 2114, and is also responsible for its stabilization. It's a kind of small electric motor with a cone-shaped needle at the end.

RXX VAZ 2114

Such a sensor is mounted on the varnish or screwed with two screws to the throttle body body. Nearby there is a throttle valve sensor that regulates its position.

Location of the IAC on the VAZ 2114

Malfunctions with it periodically occur. In this article we will talk about how to check the IAC on a VAZ 2114 yourself and for free.

Troubleshooting

The main feature of working with IAC is that its malfunction cannot be detected automatically, i.e. the computer won't show it. So, how can you check the functionality of the idle speed sensor? Only by hand! What your car can tell you if the sensor is faulty:

1. when idling, the car often stalls;
2. floating speed appears;
3. no increased speed when the engine is cold (starting it);
4. If you remove the gear, the engine may stall.

Method No. 1

Before checking the idle speed sensor on a VAZ 2114, make sure you have a tester at hand. And then look for the sensor itself.

Firstly, our IAC needs to be freed from the block with wires.

Secondly, make sure that voltage is supplied to the regulator using a voltmeter. The negative is connected to ground, the positive to the block: terminals A - D. With the ignition on, the tester should give a result of at least 12 watts. voltage.

If it is absent at all, it means that there is a problem with the power circuit or the electrical engine control unit. When the voltage is present, but it is much lower than the norm of 12 volts, it means that the battery is discharged and needs to be charged.

If the ignition circuit has been tested for serviceability, you can begin inspecting the regulator itself. At this stage, the ignition can already be turned off.

We alternately connect the terminals of our tester to pairs of outputs A and B, C and D. Normally, the resistance will be about 53 ohms. Then we change the pairs, now they are A and C, B and D. Such connections must show resistance as infinitely large.

What to do when readings deviate from normal:

1. you can clean the idle speed control with carburetor cleaner (its contacts, throttle valve, cone needle);
2. try to repair it;
3. as a last resort, buy a new one.

Method No. 2

You will need to make an IAC tester with your own hands, as in the video:

First, you need to unscrew the fastening screws and completely remove the regulator from the car. Afterwards, you need to disconnect it from the main block and apply the index finger of your right hand. It's easy to apply without creating much pressure. Why is this necessary, you ask? The secret is in the design of the regulator.

Remember, there is a tapered needle at the end of the regulator. And if the engine stops working, then the needle of a working sensor comes out completely. That’s why you need a finger, you will feel a slight push with it when the ignition starts. Accordingly, if there is no push, the device is faulty.

Agree, such an IAC check is within the reach of anyone, even a novice car owner.

Distance from the flange to the protruding rod head on the IAC VAZ 2114

What is better to buy

If the IAC check indicates the need for purchase, then you should select a part that is suitable for the series. For example, "OMEGA" No. 2112-114830; "KZTA" No. 2112-1148300-04. The last two digits (04) have special meaning.

If the previous sensor ended in number 01, and instead of it you put, say, 03, then it will be a waste of time and money: it will not work.

Therefore, it makes sense to change the sensor either to the same one, that is, with the same number, or to an interchangeable one: 01 can be changed to 02, and 03 will replace 04.

Source: http://NaDomkrat.ru/elektrooborudovaniye/kak-proverit-regulyator-xolostogo-xoda-na-vaz-2114

Checking the idle air control (IAC). Signs of malfunction of the idle air control (IAC)

Signs of a malfunctioning idle air control (IAC).

The idle air control is an actuator and its self-diagnosis is most often not provided for in the system.

Therefore, if the idle air regulator malfunctions, the “CHECK ENGINE ” lamp does not light up on all cars.

Symptoms of IAC malfunctions are in many ways similar to TPS (throttle position sensor) malfunctions, and in this case, most often the “CHECK ENGINE” lamp clearly indicates a TPS malfunction.  

     The following symptoms can be attributed to malfunctions of the idle air regulator: 

 – unstable engine speed at idle, 

 – spontaneous increase or decrease in engine speed, 

 – stopping the engine when the gear is switched off, 

 – no increased speed when starting a cold engine, 

 – reduction of engine idle speed when the load is turned on (headlights, stove, etc.).

Cleaning the idle air control (IAC).

     If the sensor does not work, then you can try to wash and clean the sensor. Cleaning the IAC is an easy and quick process. To do this we will need carburetor cleaner or wd-40.

1) First, disconnect the wire block from the sensor.

2) Apply cleaner to a cotton swab and clean the contacts.

3) Take a small Phillips screwdriver and unscrew the 2 sensor mounts.

(If there are no fasteners, then the sensor is seated on the varnish, in which case you need to remove the entire throttle assembly)

4) Take out the sensor and look at its condition:

If the sensor is covered in oil and black dirt, then the conclusion follows that in addition to cleaning the sensor, you need to clean the entire throttle valve (How to clean and wash the throttle valve?).

5) Take WD-40 or carburetor cleaner and generously spray it on the conical needle with a spring, thereby cleaning it from dirt. Then we dry the sensor and install it back.

Before installation, check the distance from the sensor body to the needle (23mm).

        If no changes are observed in the operation of the engine and sensor at idle, it means that the cone needle guides are worn out (replace with a new sensor) or the wire inside the sensor is broken.

Checking the idle air control (IAC).

      Turn off the ignition. Disconnect the harness connector from the regulator. Using a multimeter, check the resistance of the IAC windings.

The resistance between the contacts of the idle air control system A and B, and C and D should be 40-80 Ohms . If not, replace the IAC. If yes Check the resistance between terminals B and C, A and D.

The device should show infinity (open circuit). If not, replace the IAC. If so, the IAC circuit is ok.

IAC circuits

   There is another way to check: to do this, completely remove the sensor by unscrewing two screws. Having pulled out the sensor, connect the block to it and place your finger on the tip of the sensor needle without making any effort.

Theoretically, a working sensor at the moment the ignition is turned off fully extends its needle. Therefore, when you turn on the ignition, you should feel a slight push on your finger.

If this does not happen, then the sensor is not working.

Removing the idle air control (IAC).

To dismantle the idle air control you must:
1) Turn off the ignition.
2) Disconnect the four-pin IAC connector.
3) Unscrew the two mounting screws.

      Installation of the idle air control (IAC) is carried out in the reverse order, but after checking the distance from the flange to the end point of the cone needle, which should be . In addition, the O-ring on the flange should be lubricated with engine oil.

Source: http://220780alex.blogspot.com/2013/09/blog-post_6797.html

Checking and cleaning the idle speed sensor yourself

The idle speed regulator in a car is installed on the engine, in particular, on the throttle body. The vehicle model does not matter. The device can be seen next to the throttle position controller. The regulator is secured to the assembly using one or more bolts. In some car models, the sensor is fixed with varnish.

Location of the IAC in the car

The operating principle of the IAC is based on counting steps and returning the valve to its initial state.

If the driver activates the ignition, the rod on the sensor comes out completely and rests against the technological calibration hole. It is located on the throttle line.

The device then counts the steps and the valve returns to its original state. The position of the latter depends on the firmware of the control unit.

If the power unit is completely warmed up, then on VAZ cars at the time of adjustment the controller is located at about 30-50 steps. When this parameter increases or decreases, the volume of air flow that passes through the calibration hole changes.

If the rod extends, the number of translational movements increases, and when it retracts, it decreases. On VAZs the stroke of this element is about 250 steps.

A certain amount of air flow is supplied to the power unit, which is required for optimal engine operation, this allows you to regulate the speed.

User Dmitry Shark spoke in detail about the principle of operation of the idle speed controller in a car.

The air entering the internal combustion engine is analyzed using a mass flow control device.

Taking into account the resulting volume, the microprocessor module supplies the required amount of fuel to the power unit, which passes through the fuel injectors.

In accordance with the readings of the crankshaft position controller, the control module monitors the engine speed and adjusts the idle speed. This allows the required volume of air flow to be supplied to the machine engine.

If the car engine is not warmed up, then an increase in speed occurs as a result of the operation of the idle speed controller. As they warm up, their number increases. Thanks to this operating principle, the car owner has the opportunity to start driving the car without warming up the internal combustion engine.

User Alex ZW spoke in detail about the device, as well as the principle of operation of the car engine idle speed controller.

Causes of malfunctions

Causes of malfunctions in the idle speed sensor:

1. There was a break in the electrical wiring inside the controller. The problem may be associated with wear of the conductors, the appearance of oxidation at the terminals of the cable connectors, as well as a short circuit (short circuit). The contact may close due to abrasion of the insulating layer.
2. The needle guide has worn out, causing it to wear off. This is due to long-term operation of the device.
3. Contamination of the mechanical components of the mechanism, as a result of which the rod cannot move normally. When the internal combustion engine operates, dust particles pass through the air filter device and mix with engine fluid vapors and exhaust gases from the ventilation system. As a result, this contributes to contamination of the throttle valve components. The formation of carbon deposits contributes to the clogging of the bypass channel and its entry into the idle speed controller. The sensor rod begins to move with wedging, which leads to unstable operation of the internal combustion engine.
4. Another reason is clogging of the drive device of the worm-anchor mechanism. This gear is used to prevent the rotational movement of the rotor of an electric motor from the translational movement of the conical rod. If the threads of the mechanism wear out, the element will not be able to move normally.
5. Failure of the electric motor. By design, this engine is a reliable mechanism. But as a result of problems in the operation of the electrical power circuit, there is a possibility of burnout of the electric motor winding. To detect a malfunction, you will have to perform a complete diagnosis of the IAC.
6. Destruction of the sealing element. Due to damage to the ring, air flow is sucked into the mass flow sensor.

Problems related to the operation of the IAC cannot be started. If the malfunction of the idle speed sensor is not corrected in time, this will lead to a decrease in the service life of the machine’s engine as a whole.

Signs of breakdown

“Symptoms” by which you can determine a controller malfunction:

1. The car engine starts up "briskly", but a few minutes after starting it stalls. This problem appears all the time.
2. At idle, the power unit functions unstable. Engine speed can increase sharply and drop just as quickly. This is clearly audible because the jumps are serious. Such a problem can lead to vibration in the operation of the power unit, which negatively affects its functioning as a whole.
3. When the air conditioning system, heating system or other energy consumers are activated, the number of revolutions drops sharply. The same thing occurs when the optics are turned on. This sign may also indicate incorrect operation of the generator device.
4. The car engine randomly stalls when the driver shifts the gear lever. It is possible for the internal combustion engine to stop when the car is stopped at a traffic light or while coasting.
5. If a cold start of the power unit occurs, the engine speed will be minimal. In some cases, the tachometer needle does not rise above the zero position. When the driver presses the gas pedal, no action occurs and the engine power does not increase.
6. The power unit of the car begins to trip when the car moves at idle speed.

Channel Sdelaj Sam! Pljus interesting! spoke in detail about the signs of malfunctions in the operation of the vehicle's IAC.

How to check the idle speed sensor?

There are several options for checking the idle speed sensor:

• using a computer;
• using a tester;
• folk way.

Computer diagnostics

Although the IAC itself is called a sensor, this regulator does not have feedback from the engine control module and is considered an actuator.

During operation, the microprocessor unit sets the required position of the rod by applying voltage to the stepper motor.

But objectively, the control sensor cannot produce the actual departure of this element, so practical values ​​are not recorded.

As a result, if the idle speed sensor fails, the “Check Engine” indicator does not appear on the control panel.

The presence of a self-diagnosis system only allows you to register problems associated with the electrical circuit to which the device is connected. To check, you will need to connect to the diagnostic output of the computer via a special adapter. The test software is launched on the PC, which, once launched, scans all vehicle systems.

Depending on the car, IAC fault codes may be different, but usually they look like this:

• P0505 - a malfunction indicating a malfunction in the electrical circuit to which the controller is connected;
• P0506 - the idle speed control is blocked, the engine operates at reduced speed;
• P1509 - the microprocessor module has detected an overload of the controller control conductor;
• P1513 - a short to ground has occurred in the electrical wiring to which the regulator is connected;
• P1514 - the microprocessor module reports a short circuit or open circuit at +12 volts.

The VD Test channel talked about performing computer diagnostics of a car to detect faults using a tablet.

Checking IAC with a multimeter

For diagnostics, you will need a tester - a multimeter; if you don’t have one, you can use an ammeter or ohmmeter:

1. Before performing the test, the power unit of the machine is started to warm it up a little; 60 degrees will be enough. All electrical appliances and devices are turned off. Before diagnostics, you need to make sure that the throttle position controller, as well as the lambda probe, are working. Checking is not allowed if there are leaks in the vacuum and exhaust systems. You also need to make sure that the tachometer is connected correctly.
2. The engine is started. If the idle speed controller is working, it will function continuously; during operation, the regulator may hum and vibrate a little. After startup, the electrical connector from the sensor is disconnected. The number of revolutions should increase to 2 thousand per minute.
3. If this parameter has not changed, then take a tester and check the resistance level between the contact elements of the device being diagnosed. The working value should be 9-10 ohms. You need to make sure that when voltage is supplied from the battery to the device, the element is in a closed state, and when turned off, the regulator opens. If diagnostics show that the sensor does not have the required resistance or is not functioning correctly, then the IAC is not working and must be replaced.
4. The next step will be to diagnose the control current parameter. The block with wires is disconnected from the regulator, after which one contact of the plug is connected to the IAC contact element using a jumper. You can use a paperclip or a piece of cable. A multimeter configured in ammeter operating mode is connected to the second contact; the device range is from 0 to 1000 mA.
5. When the power unit is operating at idle speed, the diagnosed value should be from 400 to 500 mA; if the parameters are different, the IAC must be replaced. It should be taken into account that diagnostic equipment can show a current value higher than 500 mA. This usually happens if the conditions described in the first paragraph are not met.
6. If the diagnostics showed a lack of control current, then the microprocessor module of the car must be repaired or replaced.
7. If the car is equipped with a three-wire idle speed controller, then similar steps are performed for diagnostics, but the nuances must be taken into account. The procedure for measuring the resistance parameter should be carried out between two contact elements located at the edges. The value will be 40 ohms. Then the resistance between the extreme and middle contacts is checked. The operating value with the sensor working will be 20 Ohms.
8. The control current diagnostic procedure in three-wire devices is performed by measuring the voltage at the central contact element. This value must match the value on the battery. The operating voltage between the central and outer contact elements should be 10 volts.

User Igor Belov spoke about diagnosing the idle speed controller using a multimeter, as well as other testing methods.

Diagnostics using a tester is the most accurate diagnostic option

Folk method

Implementation of this method is only possible with an assistant:

1. The sensor is being dismantled. To do this, it is usually enough to unscrew the fixing bolts.
2. A four-pin connector is connected.
3. A finger is applied to the end of the sensor needle; no serious effort is needed.
4. The assistant gets behind the wheel and the ignition is activated. When turned on, the controller should extend the needle. If this happens, then the regulator is operational. Malfunctions should be looked for in the functioning of the throttle position controller.

How to clean the idle speed sensor?

Cleaning the IAC is performed after preparing the following tools and materials:

• Phillips head screwdriver;
• carburetor cleaner; regular alcohol, solvent or WD-40 will also work;
• spanners;
• Torx keys;
• lint-free rags, preferably light in color.

User Alexander Filimonov spoke about the nuances of cleaning the idle speed controller.

You need to clean the device like this:

1. The car engine must be turned off and cooled down.
2. The air duct connecting the filter element to the throttle body cover is dismantled. To do this, unscrew two clamps and dismantle it, this will make cleaning more convenient. The crankcase ventilation system line is disconnected and the throttle valve is removed. The cover itself is usually secured with a clamp, but access to it can be difficult. You may need several screwdrivers to unscrew it.
3. The cleaning agent is sprayed onto the closed throttle valve. This is done carefully so as not to splash other parts of the device located nearby. It is recommended to spray the product with light, short-term pressure. After completing the task, you need to wipe the damper with a lint-free cloth, and then clean it again. Only now you need to spray the liquid onto the walls of the chamber; the remaining product is removed with a cloth.
4. The unit is cleaned in the same way with the damper open. The steps are repeated until the device turns as smoothly as possible and without jamming. It should close as tightly as possible.
5. Then the block with wires is disconnected from the idle speed controller. Using a wrench of the appropriate size, remove the bolts securing the regulator. The device is dismantled; during removal, the sealing element located on the mount cannot be lost. If the damper is open, the air channel hole must be plugged with a rag. All components are cleaned, including the seat of the control device.
6. The controller is also cleaned using a cleaning agent. You must act carefully so that the rod does not move during the work. At the final stage, you need to wipe the throttle valve cover, after which all dismantled elements are installed. If the rod was displaced during the cleaning process, its position must be adjusted so that it returns.

State of the device before cleaning. Appearance of the sensor after it has been cleaned. Installation location of the idle speed controller

Replacing the idle speed sensor

The change procedure is performed as follows:

1. All actions are carried out with the engine turned off.
2. The controller installation location is being searched. It is necessary to unscrew two mounting screws from the installed sensor. The failed device is being dismantled.
3. Installing a new regulator is carried out in the reverse order. When performing the task, you need to fix the controller in the seat and tighten the screws completely. The sensor must not be secured loosely, as exposure to vibrations during movement will cause it to break.
4. During installation, it must be taken into account that the distance between the mounting flange and the controller should be no more than 2.3 cm.
5. The terminal block is being connected.
6. After connecting, you need to activate the ignition for 10 seconds. The power unit does not start. When the ignition is turned on, the microprocessor module calibrates the newly installed device. After ten seconds, the engine can be started and the functionality of the regulator can be checked.

User OVSYUK presented a visual guide to replacing the idle speed controller in a car.

Prevention Tips

Recommendations that will increase the service life of the IAC:

1. Do not allow liquid to enter the throttle valve. This will cause moisture and dirt to accumulate inside the device.
2. It is necessary to monitor the condition of the air filters. The IAC is a flow regulator, so this is important for the sensor.
3. If the car is rarely used during the cold season, then you need to find a garage for it. In this case, it is necessary to periodically start and warm up the engine and perform gas changes. This will allow the idle speed controller to develop and not freeze. After a long period of parking in low temperatures, the sensor may jam.

Video “Visual guide to replacing the controller”

User Ivan Vasilyevich spoke in detail about the procedure for changing the idle air control using the example of a VAZ car.

Source: http://AvtoZam.com/elektronika/sensor/kak-proverit-datchik-holostogo-hoda/

Signs of malfunction of the idle air control (IAC) and how to check it for functionality, clean or replace it

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

The IAC is in working condition almost constantly, so its resource is not very long, usually up to 200,000 kilometers. In the practice of repairing car engines, even with little experience, regulator failure occurs quite often.

IAC: what is it and its principle of operation

Idle air regulators are usually built according to two schemes:

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

A stepper motor is usually used as an actuator in gasoline engines. It has advantages over other drives: greater accuracy, lower current consumption, and the ability to control in pulse mode.

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

Thus, when the throttle valve is completely 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 commands from the engine control unit, regulates the width of the valve gap and, accordingly, the flow of air into the engine, on which its speed depends.

Direct-acting speed controllers on the damper directly regulate the angle of maximum closing of the damper, leaving a small gap to maintain air flow into the intake manifold and, accordingly, ensure idle speed.

Video about IAC - what it is, operating principle and design options:

The control unit usually controls the number of revolutions based on the engine speed signal coming from the crankshaft sensor.

Most engine control systems are designed in such a way that when the accelerator pedal is pressed and the speed increases, the IAC drive is turned off and remains in its last state before acceleration. Thus, the load on the regulator drive is reduced.

In diesel engines, to maintain idle speed, fuel supply control is also used by bypass type. For this purpose, high-pressure fuel pumps use a special electronic control system.

Solenoid or rotary valves are used as IAC drives in high-pressure fuel pumps. Such drives use only two levels of opening of the bypass channel - “open” or “closed”.

This method makes it difficult to accurately set the idle speed. Therefore, the valves are controlled by a high-frequency pulse-width modulated signal (PWM modulation). The larger the pulse width, the longer the bypass channel is open during the period, that is, the speed increases.

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

Signs of IAC malfunction

The main symptoms of a malfunctioning idle air regulator are:

• “swimming” of engine speed at idle;

• increased or decreased engine speed;

• spontaneous engine stop when switching the gearbox to neutral mode;

• at the time of cold start, the engine runs at high speeds, as it warms up it drops, the absence of this mode is also a sign of a malfunction of the regulator;

• reducing the engine speed when turning on an additional load (stove, headlights, brushes and other powerful consumers).

Where is the regulator located 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 is broken or the rod is jammed. Disassembly of the regulator should be done with extreme care. In some cases, it can be restored by cleaning.

The typical location of the IAC is directly on the throttle valve. Removing regulators is usually not difficult.

How to check the idle air control

Computer diagnostics usually display IAC error messages in the form of a message like “idle air control, short circuit or open circuit.” Usually, the fault is an open circuit.

This may be a malfunction of the winding (break) of the regulator itself or a violation of the electrical connection with the engine control unit. Both options should be checked.

You can check the serviceability of the windings using a multimeter in resistance measurement mode at a limit of 200 Ohms. The winding resistance of a working stepper motor is usually in the range from 30 to 100 Ohms. The windings are connected through the idle speed regulator connector according to the electrical diagram.

Video - checking, diagnosing and replacing IACs on Lanos, Chance, Forza, Cherry, Sens:

A very common cause of breakdown of the idle air regulator is a jammed rod. Moisture, foreign liquids, and dust get into it, which leads to corrosion and jamming. In order to check this, a special pulse signal generator is needed to force control of the regulator drive. Such a check is possible only at a service station. In this case, cleaning can help.

The most reliable way to check operation is to install a known-good idle air regulator from a similar engine.

How to clean

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

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

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

In some cases, the cause of a malfunction of the idle air control system is a clogged bypass channel. It needs to be cleaned first. Cleaning the canal can be done using any suitable means using soft brushes made from natural fibers.

Replacement

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

After replacing the idle air control valve, some vehicles require a calibration procedure. It is performed using diagnostic devices on special equipment.

Video - how to correctly replace the IAC:

In most cars, the calibration (adaptation) procedure is performed automatically when the ignition is turned on.

Adviсe

To extend the life of the idle air regulator, you should:

• change the air filter promptly;
• when parking the car in winter, periodically start the engine, warm it up, perform gas changes in order to develop the regulator to prevent it from jamming;
• Avoid getting foreign liquids into the throttle valve area (quick start sprays do not pose a danger to the regulator).

Video - IAC check:

May be of interest:

Source: http://voditeliauto.ru/poleznaya-informaciya/to-i-remont/regulyator-xolostogo-xoda-rxx.html