How to check if the throttle sensor is working. How to self-diagnose a faulty throttle sensor

Position sensor throttle valve(TPPS) informs the car's computer how hard you press the gas pedal. A throttle is a hole that opens or closes depending on how much air the engine needs. The harder you press the accelerator pedal, the more air will flow into the engine. The TPS monitors the throttle position to determine how much fuel the engine needs to run properly at a given time.

How to recognize faulty TPS

There are many problems that can result from a broken throttle position sensor. Here are some of the most common symptoms:

• sudden stop of the engine;
• problems with starting the engine;
• too rich or lean fuel mixture;
• increased level of harmful emissions;
• unstable acceleration, etc.

The principle of operation of the throttle sensor

TPS is a simple electronic device called a potentiometer. To better understand how to diagnose this sensor, you need to understand how a potentiometer works. A potentiometer is a moving contact variable resistor connected to a scale that transmits a voltage value based on the position of the contact. The figure below shows the circuit of the potentiometer.

TPS has three contacts:

• reference voltage;
• signal contact;
• grounding.

How to Diagnose Throttle Position Sensor Using a Multimeter

Using a multimeter is one of better ways TPS checks, and even a cheap device will do.

1. Find the TPS on your vehicle. Since it controls the position of the throttle, look for a sensor on its body.

In the figure below, the red arrow points to this sensor.

For demonstration purposes, I removed the air inlet so you can see how the throttle assembly works. This will help you when checking the sensor.

• Older vehicles use a mechanical lever on the throttle body, which is connected to the gas pedal in the passenger compartment via a cable drive (newer vehicles use an electronic accelerator pedal).
• The throttle assembly has a plate (circular disc) that acts as a door for air to enter the engine.
• When the throttle is closed (the gas pedal is not pressed), the damper is in a fully closed state.

• At wide open throttle (the gas pedal is pressed to the floor), the damper is fully open, allowing maximum air supply to the engine.

1. The next step is to provide conditions for the correct operation of the TPS. To do this, start by unplugging the electrical connector from the sensor.

Connect the black wire of the multimeter to the negative terminal of the battery and set the device to the mode direct current.

• Measure the voltage at the middle pin where the signal wire is usually connected. It should also display approximately 0 volts.

• Connect to the third pin, which should show about 5 volts. This is our reference voltage. If, when connected to the third contact, you do not see 5 volts on the multimeter, the throttle position sensor does not receive the required voltage, and this is a sign of a wiring defect on the way to the sensor. Check it for mechanical damage.

It is important to note that as long as there is 5 volts on one pin and about 0 volts on the other two, you do not have to worry about the integrity of the wiring. Remember that the signal pin is usually the middle pin in the connector and note where the 5 volts and ground are located.

1. Connect the wiring connector to the TPS and connect the multimeter probes to the signal and ground contacts using paper clips (see photo below).

1. Connect the positive (red) probe of the multimeter to the signal wire (middle pin), and the black probe to the ground wire. Set your multimeter to DCV mode

1. With this connection, the multimeter should show approximately 0.9 volts. Exact figures may vary depending on the vehicle model.
2. Rotate the throttle body lever and note the change in voltage. If you are not comfortable doing this, you can put the multimeter on windshield, turning the screen to the interior of the car, get behind the wheel and press the gas pedal. The result will be the same.
3. If the throttle position sensor is working correctly, you will see a smooth change from the base voltage (in our situation, about 0.9 volts) to the maximum value (about 4.47V). Turn the lever or slowly press the gas pedal, try to see the "peaks" of voltage. Sudden surges or drops in voltage are what we are interested in. For example, if you press the gas pedal about halfway and the display shows about 2.5 volts, sharp spikes above 4 volts or drops to 1 volt indicate TPS malfunctions.

This is due to the physical wear of the throttle sensor. If you find a section where the voltage jumps every time you pass it (either on the way up or down), this is a sign of worn out resistor. Information about this voltage surge is transmitted to the electronic unit control, causing the computer to think that you have sharply pressed or released the gas pedal.

If the TPS check showed that the sensor is faulty, it will not be difficult to replace it. As a rule, it is fastened with only two bolts. It is only necessary to disconnect the electrical connector, unscrew the mounting bolts, pull out the sensor and install a new one.

The throttle position sensor is designed to transmit information about the state of the bypass valve in a specific period to the ECU of a car engine. This mechanism is a combination of a fixed and a variable resistor.

In total, the maximum resistance of the device is approximately 8 ohms. The TPS device includes 3 contacts. A voltage of about 5 V is applied to 1 and 2, the 3rd contact is a signal, connected to a specific controller.

The PDZ sensor is mounted on the throttle body and reacts to its opening or closing. The resistance of the device also changes:

• when the throttle valve is fully open, the voltage value on the signal contact will be at least 4 V;
• with a fully closed remote control - up to 0.7 V.

Any voltage changes are regulated by the controller. Accordingly, the amount of fuel required to create an air-fuel mixture is regulated.

If the throttle does not operate correctly, the voltage may go beyond the established limits, which often leads to a violation of functionality. power unit and sometimes to complete failure.

It should be noted that a breakdown of the PDS sensor is often the cause of incorrect operation of the gearbox. Repair car engine and the checkpoint is a rather time-consuming and costly undertaking. Therefore, when identifying signs of a malfunction of the throttle sensor, it is recommended to check the functionality of the gearbox.

The main signs of a device malfunction

You can identify problems in operation by the following signs of a malfunction of the TPS, indicating a breakdown of this particular mechanism:

1. Regardless of the operating mode of the motor, the revolutions idle move fickle.
2. If you suddenly release the gas pedal, when switching the gearbox, the engine stalls.
3. The power of the motor drops significantly.
4. In the operation of the engine at idle, the revolutions are inconsistent.
5. Fuel consumption has increased markedly.
6. Despite the smooth depressing of the gas pedal, jerks are noticeable when accelerating.

In some situations, the indicator lamp may light up. check engine, while it does not go out for some period. This signal should not be neglected either: it is imperative to check and eliminate errors in the operation of the device.

Checking the performance of the TPS

If during operation vehicle at least one of the signs of a malfunction of the throttle position sensor has been detected, its functionality must be checked. For this, the owner of the car does not require any special knowledge. It is enough to have a multimeter and know a clear sequence of actions.

The main thing to remember is that the Check Engine is a light bulb that is installed specifically to signal the driver about a faulty engine. If it lights up, then you need to immediately contact the service station or fix the problem on your own.

If there are no problems, the light will come on when the engine is started and go out instantly when the diagnosis is completed. If the Check Engine stays on, then there is a problem in the system. In this case, an experienced specialist is indispensable.

Regarding the definition of throttle malfunctions, the symptoms of which were identified during the operation of the car, there is a certain algorithm of actions:

1. The first step is to turn off the ignition, inspect the instrument panel, notice whether the Check Engine indicator lamp is on or not, which indicates the presence of problems. If the indicator does not light up, you need to get under the hood and check the TPS.
2. Next, you need a multimeter - a special device for checking the operation of the throttle sensor.
3. It is necessary to determine the presence of a "minus". In order not to discard each wire separately, it is worth piercing the right wires and measure them.
4. In the same way, the search for "mass" is carried out. During the period of checking the mechanism, it is not necessary to turn on the ignition.

The purpose of performing preliminary actions is to check the availability of power supply to the PDZ sensor. The voltage depends on the make of the car. For example, for some machines it can be as low as 5 V, while for other models it can be 12 V.

Algorithm of actions to determine malfunctions of the TPS, the symptoms of which were detected while the vehicle was moving:

• you need to turn on the ignition and, in turn, pierce the wires of the required chain with a multimeter. The display of the device should show a voltage indicator of 0.7 V;
• manually open the throttle valve: the voltage value must be greater than 4 V;
• the ignition is turned off, one connector is discarded. In the area between the output of the slider and the wire (which remains), the multimeter probe is connected;
• now you need to manually scroll the sector and observe the readings of the measuring device. If there is a smooth increase in values ​​without sharp jumps, then the PDZ sensor is working normally. In the opposite situation, we can talk about damage (wear) of the resistor track.

These indicators affect the correct functioning of the electronic control unit (ECU), which controls the main working processes of the automobile engine, the supply to the injectors fuel mixture. If inaccurate numbers are fed to the computer, then the control unit will make the wrong decisions.

For example, the throttle valve is fully open, and the electronic device shows that it is closed. If such symptoms are present, this is a clear malfunction of the throttle sensor, it must be replaced.

Causes of sensor failure

It is impossible to completely prevent breakdowns of units, parts, electronic mechanisms of vehicles.

Possible reasons for the failure of the TPS:

1. Loss of contact between slider and resistive layer. The reason is that the tip has broken, causing scuffing on the substrate. In this case, the throttle sensor may continue to function (not correctly enough) until the resistive layer is completely erased. As a result, the core fails completely.
2. A linear increase in the voltage of the output signal is not provided due to a violation of the deposition of the base at the beginning of the slider stroke.

It must be understood that not a single indicator on the instrument panel will tell you about such a breakdown, and self-diagnosis of the car is not provided. The existence of a malfunction can only be assumed in the event of unstable operation of the motor in different operating modes.

Everything modern cars have in their design a lot of electrical and electronic devices. With their help, the control and automatic adjustment of the parameters of the functioning of various components, assemblies and systems is carried out. They can be very complex and expensive, like, for example, an electronic engine control unit (ECU), or very simple. It is noteworthy that many "little things", the cost of which is quite small, play a very important practical role in practice. For example, if signs of a malfunction of the throttle position sensor are found, then if they are left unattended, a quick and very expensive repair of the power unit is practically guaranteed.

What is the throttle position sensor for?

Such a part is designed to transmit information to the electronic engine control unit about the exact state in which the bypass valve is at a given moment in time. In fact, it is a combination of a fixed and a variable resistor, and its maximum total resistance is approximately 8 ohms. The TPS has three contacts in its design, and two of them are energized (usually its value is about 5 V), and the third is a signal and is connected to the corresponding controller.

GM throttle position sensor

The throttle position sensor is mounted on its body and reacts to the rotation of the axis when it either opens or closes. Accordingly, its resistance also changes: if the damper is fully open, then the voltage at the signal contact is at least 4 V, and if it is fully closed, then a maximum of 0.7 V. The controller monitors all voltage changes, as a result of which the amount of fuel supplied to form an air-fuel mixture.

If the TPS does not work correctly, then it will be either less or more than necessary, which can lead (and often does lead) to various malfunctions in the operation of the power unit, and sometimes even to its failure. It should also be said that a malfunction of the throttle position sensor is quite often the cause of problems with the gearbox. Repairing both the engine and the gearbox is a very costly undertaking, so if signs of a malfunction of the throttle position sensor are found, then it must be checked.

Symptoms of a faulty throttle position sensor

The throttle position sensor in the fuel system plays a “smoothing” role, and therefore, if it is working, the car drives smoothly, smoothly, when you press the gas pedal, it demonstrates “responsiveness”. If the TPS is faulty, then this can be determined by the following signs:

• The engine starts to start badly;
• Significantly increased fuel consumption;
• The car rides "jerks";
• Seriously increases the number of engine revolutions at idle;
• When the car accelerates, it does so with some delay;
• From intake manifold"clapping" sounds are heard;
• The engine stalls at idle;
• The Check Ingine light either stays on or flashes intermittently.

If at least one of the symptoms listed above is manifested, then it is likely that the TPS is faulty. As practice shows, in most cases, the breakdown of this part is associated with its natural wear and tear. The fact is that the variable resistor, which is available in the design of the throttle position sensor, has a sprayed base layer, which the metal contact moving along it wears out over time. Accordingly, the TPS begins to issue incorrect data.

Experienced experts say that the surest sign that the throttle position sensor is faulty is the "swimming" of the idle speed of the power unit. If such symptoms are found, then it is necessary to contact the station Maintenance or do the diagnostics yourself.

Video about the signs of a TPS malfunction

How to test the throttle position sensor

It is not difficult to do this, and from the equipment you only need a multimeter or voltmeter. It is necessary to turn the key in the ignition lock, and measure the voltage value between the signal contact and the "minus". It should be no more than 0.7 V. After that, it is necessary to fully open the damper, and then measure again. The value should now be over 4V.

How to check TPS with a multimeter

Next, you need to turn on the ignition completely and measure the voltage between the signal and any other output of the TPS. Next, you need to slowly turn the sector, watching how the voltage changes. It should be carried out smoothly, without jerks. If they are, then this is a symptom that the throttle position sensor is faulty.

Unfortunately, due to their design and damage characteristics, throttle position sensors are non-repairable parts. Therefore, if it turns out that the TPS is really faulty, then it must simply be replaced with a new one. At the same time, it is recommended to choose not an outdated resistive film, but a modern non-contact model. It differs in that it functions according to the principle of the magnetic effect, consists of such parts as a magnet, a rotor and a stator, and does not have parts rubbing against each other in its design.

The electronic control unit sets the operating modes injection system nutrition based on indications. So, he monitors the position of the crankshaft, the amount of air supplied, the composition of the exhaust gases. The ECU also monitors the position of the throttle, which allows it to determine how much air and gasoline needs to be supplied to the cylinders. The throttle position sensor (abbr. - TPS) is directly responsible for this.

Purpose of the throttle position sensor

The throttle position sensor detects the throttle position angle and throttle opening speed. Based on this data, the ECU generates a pulse that is applied to the injectors. For example, when hard pressing on the gas pedal, thanks to the TPS readings, the ECU will increase the duration of the pulses going to the injectors, which will provide increased fuel supply, and also adjust the ignition angle.

It is installed directly on the throttle assembly itself and has a rigid connection with the damper axis rod, which allows the sensor to constantly respond to changes in its position.

Types and design of TPS

Mechanical Throttle Diagram:
1) coolant supply pipe;
2) branch pipe of the crankcase ventilation system;
3) coolant outlet pipe;
4) throttle position sensor;
5) idle speed regulator;
6) branch pipe of the gasoline vapor recovery system;

There are two types of PDZ sensor that are used on cars:

1. contact (potentiometer);
2. non-contact (magnetoresistive).

The first is used by all car manufacturers, and the second is sold separately and used as an alternative to the contact element.

Any potentiometer consists of two main components - a slider (movable element) and resistive tracks, relative to which the movement is carried out. These two elements are constantly in contact with each other.

Contact TPS

The principle of operation of such a throttle sensor is very simple. The slider has a rigid connection with the damper axis. When you press the accelerator, the damper opens, which leads to the rotation of the axis, while the slider also moves, which changes the length of the resistive tracks that are involved in the electrical circuit.

This throttle position sensor has three wire connections. One of them is mass, and the other two are “positive”, but voltage is applied to one of them, and the value is removed from the second.

Device and principle of operation

And everything works like this: when the damper is fully closed, the slider is in its extreme position, which provides a minimum voltage at the output - 0.5-0.7 V, since only a small section of the tracks is involved in the circuit. When you press the accelerator, the damper begins to open, and the slider moves, increasing the length of the resistive tracks involved in the circuit, which increases the resistance and in direct proportion to it - the output voltage.

With the damper fully open, the resistance is maximum and the voltage indicator is also (4 V and above). The electronic unit reacts to all these voltage changes.

Magnetoresistive TPSs are somewhat different in design. The principle of its operation is based on the change in voltage from the influence of a magnetic field. Such a PDZ sensor also has a slider, but it does not come into contact with another component, it has a permanent magnet. The second element of the sensor is electronic, and sensitive to changes in the magnetic field that the slider creates. That is, the operation of this is quite simple - when opening the damper axis, the slider shifts, due to which the magnetic field also moves, and the electronic element reacts to this.

Magnetoresistive throttle sensors are more advanced and break less often, but they are also more expensive than conventional potentiometric TPSs. But since the latter are more common, we will consider them in the future.

Failure and signs of malfunction of the PDZ sensor

Video: Problems with the throttle position sensor (TPS)

The resource of the throttle sensor has not been precisely established, it can work out even 60 thousand kilometers, and it may already create problems even after 5 thousand km.

There are several signs that signal problems with the operation of the DPS:

• difficult start power plant;
• stop the engine in "neutral";
• increased idle speed;
• the occurrence of jerks during acceleration;
• increase in gasoline consumption;

In addition to these signs, on many cars on-board computer starts to issue an error signal indicating a malfunction of the throttle position sensor.

The reason for all these phenomena is usually the contact pair - the slider and the tracks. In some cases, the problem begins to create an erased resistive layer of the track at the extreme position of the slider. As a result, the resistance in this area increases significantly, and with it the voltage. And it turns out that when the damper is closed, a voltage is supplied to the electronic unit, the value of which corresponds to a fully open throttle.

The second reason for the exit may be due to the contact tips of the slider. If they are damaged, they very quickly begin to overwrite the resistive layer of the tracks.

If there is a breakdown in the operation of the PDZ sensor, the electronic unit switches to emergency operation and for control fuel system stops taking data from this sensor. In this case, the operation of the computer is based on the readings and.

Check and replacement

Note that most of the signs of a malfunction of the throttle position sensor are inherent in other sensors. Therefore, it is necessary to know how to correctly identify whether the throttle sensor is really the cause of the malfunction of the power plant.

Of course, that won't be a problem. We connected it, set the error code, decoded it and found that the TPS was faulty. But such a device is not always at hand.

You can check the damper sensor using a conventional multimeter set to measure voltage. The work on diagnosing the throttle sensor is simple and even a beginner can do it.

Video: How to check dpdz, check according to the manual

To check, it is necessary to connect the probe of the device to the “negative” output (usually black) and the “positive” one, from which readings are taken. To identify it, you need to turn on the ignition and take a measurement. If the display shows a value of 4-5 V, then the probe is connected to the supply terminal and should be reinstalled to another one.

If the sensor is working, then after connecting the probe to the required output, the value on the display should drop to 0.5-0.7 V. For further verification, slowly open the throttle by hand. In this case, the voltage at the terminals should increase, and with the damper fully open, its value should be set at 4-5 V. After releasing the throttle, the multimeter readings should decrease.

If these measurement conditions are not met, then the TPS is faulty. Its design is non-separable, so it cannot be repaired, and if it breaks, it is simply replaced. Although some still try to assess the state of the constituent elements, having previously disassembled it.

You can make a diagnosis by gently prying and removing the top cover, which is glued to the case. After that, we will get access to the plate with resistive tracks, to which the leads are soldered. After soldering the leads, you can remove this plate and evaluate the state of the resistive layer of the tracks and the contact tips of the slider. But it is often impossible to restore damage and wear, so you should not bother with disassembling this element, but immediately purchase a new one for replacement.

All you need to replace is a screwdriver and a new throttle position sensor. Before unscrewing the two mounting bolts, disconnect the block with wires suitable for it. Then we unscrew the fasteners and remove the defective element, and install a new one in its place, making sure that it sits tightly on the axle rod. We fix the installed throttle sensor with bolts and connect the block.

Due to the unreliability of the throttle position sensor - TPS VAZ 2110 - the motorist has to determine the signs of a malfunction on his own. The general symptoms that appear when this meter breaks down can indicate a dozen more different problems. In order to accurately diagnose the failure of the sensor, it is worth figuring out how to check the TPS yourself and then successfully replace it without resorting to the help of a car service. The method will also be useful to owners of VAZ 2112-2115 and Lada Priora cars.

Location and principle of operation of the element

All cars of the "tenth" family with an injector, including the latest VAZ 2115 models, are equipped with many sensors. They are located at various points and are busy measuring various parameters, transmitting data in the form of electrical impulses to the processor that controls the operation of the engine. The location of the meters depends on their purpose, so the VAZ 2110 throttle position sensor is not difficult to find, it is in the same block with it. The same element is installed in the Lada Priora car.

The principle of operation of the device is very similar to the operation of a mechanical variable resistor, which have long been used in radio equipment to control the volume. Inside the case there is an element with a resistive coating, along which the slider moves. One contact is connected to this element, the second to the slider, and the third to ground. The device operation algorithm is as follows:

1. A voltage of 5 V sent by the controller passes to the throttle valve sensor VAZ 2115. When the damper is fully closed, the resistance of the resistor is maximum, the controller receives only 0.3-0.7 V back.
2. When the damper, which is mechanically connected to the slider of the part, is turned, the resistance decreases, and the output voltage increases.
3. When the passage is completely open to air (the accelerator pedal is pressed to the limit), the resistance of the element is minimal, and a voltage of at least 4 V reaches the processor.

Based on the increase or decrease in the reverse voltage, the processor calculates the proportions of air and fuel in the mixture, as well as the duration of the signal applied to the injectors. True, when analyzing data, the controller gives preference to the readings of the air flow meter (DMRV), so malfunctions of the TPS do not lead to a complete stop of the car.

But with a sharp press on the accelerator pedal, the priority of the throttle sensor increases, since the controller needs to quickly supply a large amount of fuel to the cylinders. Given the sharp drop in resistance, indicating the full opening of the damper, it gives a signal to the injectors to inject an additional portion of fuel. The principle is similar to the action of a pump - an accelerator on carburetors, injecting fuel directly into the manifold using a membrane.

Accurate diagnosis of the state of the element

When the TPS starts to function incorrectly or fails completely, the fuel supply process is disrupted during a sharp acceleration of the car.

Therefore, the first sign of a sensor failure is jerks and dips when trying to dynamically accelerate.

Secondary symptoms look like this:

• when coasting downhill and the gear is engaged, the engine may stall and start again, causing jerks;
• the engine can stall both when you sharply press the gas pedal, and when it is released;
• fuel consumption increases.

The listed signs are of a general nature. Therefore more is needed fine check to make sure that the TPS is malfunctioning or, conversely, to exclude it from the list of parts responsible for changing the behavior of the machine.

An accurate check of the state of the element is carried out with a special device - a multimeter equipped with contacts in the form of needles. First of all, you need to make sure that dashboard the “Check Engine” display does not light up, which indicates a breakdown elsewhere, and the damper sensor has nothing to do with it. The further course of action is as follows:

1. Switch the multimeter to the resistance measurement mode and, with the ignition off, find the negative wire.
2. Turn on the ignition, move the switch to the voltage measurement mode and check it at the output of the sensor. The value must not exceed 0.7 V.
3. Slowly open the damper manually. The voltage should also increase smoothly and, when fully opened, remain at a level of at least 4 V.
4. Turn off the ignition and connect the contacts to the input and output wires, measure in ohmmeter mode. Slowly turn the damper and check that the resistance of the circuit decreases without jerking.

If the voltage indicators do not correspond or are absent at all, then the main reason lies in a faulty TPS. When the voltage and resistance of the resistor "jumps" when the damper axis is turned, this indicates wear of the resistive coating. Both defects definitely lead to the replacement of the part, it is impossible to repair it.

How to change a part?

Replacing the throttle position sensor in a VAZ car of the "tenth" family and Lada Priora is quick and easy. But there is one question - what type of sensor to choose? The fact is that new non-contact elements of increased reliability and equally high cost have appeared on the market.

They do not have a resistive film, and the principle of magnetic induction is used for operation. So, if possible, it’s better to put one on your “top ten” and forget about the troubles with the TPS for a long time.

The replacement operation is performed as follows:

1. Disconnect the battery and disconnect the sensor from the connector.
2. Unscrew the fastening bolts and remove the part. Don't lose the foam pad if you don't have a new one.
3. Install new element with gasket and connect all wires.

If the diagnostics and replacement are carried out correctly, then the engine should stabilize in all modes.