Connector to the idle speed control (4 terminals) injector for VAZ 2112-2115, Niva

Many car owners unwittingly became acquainted with the mysteries of the idle speed sensor on their VAZ 2114. The real name of the controller is the idle speed controller (IAC). This is a complex unit in the system of injection engines, which is commanded by electronics (among motorists, “brains”). In case of incidents with IAC, the engine begins to “act up”, causing discomfort and troubles to the driver. Next, we will tell you where the idle speed sensor of the VAZ 2114 is installed, what signs indicate its error, and how to change the IAC yourself.

Device

Modern automakers use 3 types of idle speed sensor: solenoid, rotary and stepper. For VAZ 2114–2115 the latter type is used. IAC is a stepper mini-electric motor that opens/closes the air duct of the intake manifold of the internal combustion engine, thereby regulating the speed (similar to a bolt on a carburetor).

The IAC design has a ring magnet, a lead screw (needle) and 2 windings. When voltage is applied to the magnet and windings, an electromagnetic field appears. As a result, the lead rotor begins to rotate, thereby driving the lead screw through the worm gear. Depending on the position of the rotor, the needle valve is able to control the opening/closing of the air duct of the intake manifold.

For reference. What is a step? This is the distance between the conical shut-off valve (IAC tip) and the intake manifold. It is measured by the number of full rotations of the rotor.

IAC for VAZ 2114 - where to find it, principle of the device

The idle speed sensor in the electronic injector system is needed for dosed air supply at idle speed - this is necessary to prepare the required proportion of the fuel mixture depending on the number of revolutions and load on the engine. The sensor is also called a regulator, but they are the same device.

Where is the idle air control valve located? The idle speed sensor of the VAZ 2114 (VAZ 2115) is fixed with two screws on the throttle mechanism; it is made in the form of a barrel. Inside the barrel (case) there is an electromagnetic mechanism; outside the case there is a shut-off valve that moves and regulates the air supply bypassing the throttle valve.

DXH is located in the throttle assembly (DU)

For convenience, all movements of the rod are measured in steps - a total of 255 stroke steps.

The operating principle of the device is as follows:

• Before starting the internal combustion engine, the valve is retracted and does not block the bypass channel at all (120 steps);
• The engine starts, and under the control of the ECU, the rod extends to a position that ensures stable operation of the engine at idle speed (idling speed);
• As the internal combustion engine warms up, the rod extends and the bypass channel closes (approximately 20-50 steps). The air supply is proportional to the fuel injected into the cylinder;
• When the ignition is turned off, the valve first closes the channel (0 steps) and then returns to its original position (120 steps);
• When you restart, everything repeats again, but if the engine is warm, the rod is already in a different, more optimal position. Due to the idle speed sensor, the quality of the fuel mixture and economical consumption are maintained.

As the throttle valve moves, the rod also moves, so it is constantly in motion.

Principle of operation

The balanced relationship of the injection engine components is adjusted by the electronic unit (ECU). When you turn the ignition key on a VAZ 2114, the IAC needle closes the air hole on the manifold. After the engine starts, the ECU calculates the required number of steps and sets the regulator needle to the working position, slightly opening the air channel to lean the mixture.

Taking into account the engine temperature and the position of the needle, the ECU regulates the further operation of the internal combustion engine. On a cooled VAZ-2114 engine, the idle speed sensor will again close the air valve, thereby enriching the mixture and increasing the speed.

For reference! The number of steps is determined by the software (firmware). For example, on a hot engine with a “January 5.1” controller it is usually 110 shg., and on a Bosch - 50 shg. Maximum stroke 250 shg.

Counterfeits and how to avoid them

It is not always possible to buy a VAZ 2115 idle speed sensor of good quality. The fact is that there are various underground companies that manufacture underground products. Of course, you can try to return the product to the store, the main thing is not to lose the sales or cash receipt issued by the store. But in order not to fall for a counterfeit next time, you need to learn to distinguish a fake from an original product.

When purchasing, pay attention and look at:

1. For packaging. It should have a quality control stamp, a good quality seal;
2. The spring on the original valve is black with a small number of turns. Frequent turns of light-colored springs are a sign of counterfeit;
3. The O-ring on the original body is red. Regulators with a black seal are usually fake;
4. The date of manufacture is stamped on the back of the connector end. It should be knocked out neatly and straight;
5. The rivets on the body of the original sensor are smooth and do not wobble;
6. The number on the tag of the original part corresponds to the manufacturer's number; the numbers have already been listed here above.

IAC on VAZ 2114 - original and fake

Fault marker and cause

It is very difficult to calculate the breakdown of the IAC. The VAZ on-board computer is primitive and cannot always detect a failure in the system. The owners do diagnostics several times, but there are no errors on the scanner. At the same time, the car works poorly, and the “Check Engine” is stubbornly silent. The owners of the “four” had no choice but to use samples and replace spare parts to determine the cause. Thanks to them, the main symptoms of a malfunction of the idle speed sensor are now known:

• poor starting of the internal combustion engine, especially in winter;
• floating engine speed when hot, in the range of 850–1100;
• the engine freezes if you put the gear in neutral or 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 main reason for DX failure is natural wear and tear. As a rule, wear appears in the lead screw and rotor. Due to backlash, the ECU cannot accurately adjust the needle pitch. Sometimes the winding burns out as a result of a short circuit. But the most common reason is contamination of the cone valve.

IAC VAZ 2114 signs of malfunction

There are certain signs of a malfunction of the IAC, by which you can understand that the IAC sensor is faulty:

1. The idle speed is constantly changing - it either increases or falls (the speed floats).
2. When you shift the throttle when you release the gas pedal, the engine stalls. It may also be that the internal combustion engine does not idle at all.
3. The engine is unstable at 20 rpm.
4. On a cold internal combustion engine there is no warm-up mode, that is, increased speeds are not set.
5. Elevated speeds are maintained all the time (for example, 1500 rpm).

These signs of a malfunction of the air flow sensor do not always indicate a bad sensor; it is quite likely that the mass air flow sensor is not working.

Which to choose

If symptoms or diagnostics confirm that the idle air regulator on your VAZ 2114 is defective, then all you have to do is go to the store for a new sensor. Independent auto industry experts and service workshop specialists recommend purchasing an original IAC. Its number is 2112-1148300-02 (sometimes ending: 01, 02, 04). If there is no factory part, then you can replace it with a worthy analogue.

Table 1. Price of idle speed sensor on VAZ 2114

Source: autopiter.ru

In addition to the above, the products of the manufacturers “Omega” and “KZTA” have proven themselves well.

How to check IAC

There are a lot of counterfeits on the spare parts market. Popular parts are often counterfeited in poor quality. Even some car owners have complaints about Omega, although the majority of VAZ users praise this manufacturer’s IAC. Sometimes you come across outright dummies. Therefore, service workshop specialists are recommended to organize a check of the idle speed sensor before installation on the VAZ 2114.

Self-diagnosis will require a multimeter, which should be switched to an ohmmeter. The IAC has two windings, and there are four outputs on the block: A, B, C, D. First we test A and B (first winding), then C and D (second winding). For model 2112-1148300-02 the natural resistance is 51 (±2) Ohms, and for 2112-1148300-01 - 53 (±5) Ohms. If the parameters on the multimeter tend to infinity, then there is probably an open circuit in the winding circuit.

Attention! The needle on the new regulator should stick out from the body no more than 23 mm, that is, be in a half-closed position. If it protrudes strongly from the body of the regulator, then during installation the splines of the lead screw can be damaged. Car service specialists will help you return the needle to the lower position.

How to check a sensor with a multimeter

Using a multimeter, you can diagnose the VAZ-2109 idle speed sensor (injector) in two ways: first, measure in ohmmeter mode, then in voltmeter mode.

If you close the contacts on the CD and AB plugs, the multimeter should show a resistance in the range of 40-80 Ohms. If you close the DC and AD contacts with probes, then the multimeter on a working IAC will show infinity.

In voltmeter mode, the voltage on the sensor when the ignition is on should be 12-20 V.

Replacement

Before you begin replacing the idle air control on a VAZ 2114, you need to prepare. It is better to carry out repairs in a well-lit garage, since on a 1.6 engine (16 valves) you will have to “unfasten” the throttle assembly. On 8-valve engines, craftsmen do without dismantling this mechanism. But sometimes the screws cannot be unscrewed (especially the lower one), so you have to disconnect the fuel supply unit from the manifold, and at the same time clean the dirty channels.

To replace the IAC yourself, you will need a simple set of tools: a durable medium-sized Phillips screwdriver, a 13 mm wrench (head), WD-40 lubricant, aerosol carburetor cleaner and a rag. There is a gasket between the throttle body and the intake manifold. Quite often it is in poor condition due to prolonged use. It’s better to buy a new one in advance (price 30–40 rubles). Step-by-step instructions for replacing the IAC VAZ 2114 (8–16 valves) look like this:

1. Secure the car with the handbrake.
2. Remove the negative terminal from the battery.
3. Remove the engine protective screen (for 1.6).
4. Loosen the clamps on the crankcase exhaust pipe and the corrugated pipe.

5. Disconnect the corrugation from the throttle assembly.
6. Remove the upper idle crankcase ventilation pipe.
7. Remove the throttle cable.
8. Unscrew the 2 nuts of the throttle assembly and remove it from the studs.
9. On the left, below, find the location of the IAC.
10. Unplug the power plug from the sensor.
11. Unscrew the 2 screws of the regulator using a Phillips screwdriver.
12. Clean the assembly from carbon deposits and dirt using carburetor cleaner.
13. Coat the rubber ring of the regulator with machine oil.
14. Install the IAC into the throttle mechanism.
15. Collect everything in reverse chronology.

Attention! Once you have finished replacing the idle speed sensor, do not try to start the car. First you just need to turn on the ignition and wait 10–15 seconds. The system will automatically adjust the IAC to the operating position. Then it is recommended to repeat the operation 3-4 times (masters call this “registration”). Only then can you start the car, warm up the engine and evaluate its performance.

Diagnostics on the stand

The simplest stands for checking IAC will cost the average car enthusiast 1,500-2,000 rubles. Replacing the idle speed sensor on a VAZ-2109 will cost 300 rubles. Therefore, purchasing a stand is not economically feasible. You can assemble a simple stand with your own hands. The circuit consists of a charger from any mobile equipment with a voltage of 6 V, a plug block and a test lamp. If the lamp lights up during the test, then the IAC is faulty. If the lamp burns at half intensity, then the device is working properly.

Where to buy car accessories

Spare parts and other products for the car are easily available for purchase at auto stores in your city. But there is another option that has recently received significant improvements. You no longer need to wait a long time for a parcel from China: the AliExpress online store now offers the opportunity to ship from transshipment warehouses located in various countries. For example, when ordering, you can specify the “Delivery from the Russian Federation” option.

Follow the links and choose:

Functions

The IAC regulates the amount of air entering the engine when the throttle valve is closed. This suggests that the IAC performs the functions of automatically adjusting the specified engine speed when idling.

The regulator also takes part in the process of warming up the engine to optimal operating temperatures in winter. The operating temperature range of the IAC is quite wide - from -40 to +130 degrees Celsius.

The IAC, despite such important functions, is small in size and consists of three main elements:

• Stepper electric motor;
• Spring;
• A rod with a cone-shaped needle at the end.

The idle speed control is mounted on the throttle body with a pair of screws.

IAC location