BME280 - barometric pressure, humidity and temperature sensor

see also

P0107 - DBP signal low

1 0 978

Error P0108

56 0 40k

How to unscrew a broken bolt

3 1 14k

How to remove the exhaust manifold if the pin is stuck

4 0 17k

If you suspect a malfunction of the absolute air pressure sensor in the manifold, car enthusiasts are interested in the question of how to check the DBP with their own hands. This can be done in two ways - using a multimeter, and also using software. However, to perform a DBP test using a multimeter, you must have the car's electrical diagram on hand so that you know which terminals to connect the multimeter probes to.

Scheme

Connection diagram for connecting the atmospheric pressure sensor to the Arduino Uno board

Schematic diagram of connecting a barometric pressure sensor to an Arduino Uno board.
The SCP1000 barometric pressure sensor can read both air pressure and temperature and report them via an SPI connection. For more information about the SCP1000 control registers, see the technical description.

Symptoms of DBP malfunction

If the absolute pressure sensor (also called MAP sensor, Manifold Absolute Pressure) fails completely or partially, the failure appears externally in the following situations:

• High fuel consumption. This is due to the fact that the sensor transmits incorrect data on the air pressure in the intake manifold to the ECU, and accordingly, the control unit issues a command to supply more fuel than necessary.
• Reduced engine power. This manifests itself in poor acceleration and insufficient traction when driving the car uphill and/or when loaded.
• There is a persistent smell of gasoline in the throttle valve area. This is due to the fact that it is constantly overflowing.
• Unstable idle speed. Their value either falls or rises without pressing the accelerator pedal.
• Engine “dips” during transient conditions, in particular, when changing gears, starting the car, or changing the throttle.
• Problems starting the engine. Moreover, both “hot” and “cold”.
• Formation of errors in the memory of the electronic control unit with codes p0105, p0106, p0107, p0108 and p0109.

Most of the troubleshooting symptoms described are general and can be caused by other reasons. Therefore, it is always necessary to perform comprehensive diagnostics, and you need to start first by scanning for errors in the ECU.

Signs of a malfunction and how to check the DTVV on Lanos

Having understood the principle of operation of the Lanos air temperature sensor, you should consider the factors indicating its malfunction, as well as the need for testing. To do this, we pay attention to the following factors:

• Detection of unstable engine idle speed
• The occurrence of interruptions during the operation of the internal combustion engine
• Swimming revs
• Reduced engine power and reduced acceleration
• Problem starting the engine
• Constant or periodic illumination of the "Check Engine" indicator on the instrument panel
• Error on the on-board computer with the corresponding code
• Spontaneous stopping of the internal combustion engine (engine stalls)
• Increased fuel consumption due to incorrect determination of intake air temperature

How does an absolute pressure sensor work?

Before checking the absolute air pressure sensor, it is necessary to understand in general terms its structure and operating principle. This will facilitate the verification process itself and the accuracy of the result.

Thus, in the sensor body there is a vacuum chamber with a thermistor (a resistor that changes its electrical resistance in accordance with changes in ambient temperature) and a membrane, which are connected via a bridge connection to the electrical circuit of the car (roughly speaking, to the electronic control unit, ECU). As a result of engine operation, air pressure changes, which is recorded by a membrane and compared with vacuum (hence the name - “absolute” pressure sensor). Information about pressure changes is transmitted to the ECU, on the basis of which the control unit makes a decision on the amount of fuel supplied to form the optimal air-fuel mixture. The full sensor operation cycle looks like this:

• Under the influence of pressure differences, the membrane is deformed.
• The specified deformation of the membrane is recorded by a thermistor made on the basis of a piezoelectric element.
• Using a bridge connection, the variable resistance is converted into a variable voltage, which is transmitted to the electronic control unit.
• Based on the information received, the ECU adjusts the amount of fuel supplied to the injectors.

Modern absolute pressure sensors are connected to the ECU using three wires - power, ground and signal wire. Accordingly, the essence of the test often comes down to using a multimeter to check the resistance and voltage on the specified wires under various operating conditions of the engine in general and the sensor in particular. Some MAP sensors have four wires. In addition to the above three wires, they add a fourth, through which information about the air temperature in the intake manifold is transmitted.

In most cars, the absolute pressure sensor is located directly on the intake manifold fitting. On older vehicles, it may be located on flexible air lines and attached to the vehicle body. When tuning a turbocharged engine, the DBP is often located on the air ducts.

If the pressure in the intake manifold is low, then the signal voltage produced by the sensor will also be low, and vice versa, as the pressure increases, the output voltage, transmitted as a signal from the DBP to the ECU, also increases. So, with the damper fully open, that is, at low pressure (approximately 20 kPa, differs for different machines), the signal voltage value will be within 1...1.5 Volts. With the damper closed, that is, at high pressure (about 110 kPa and above), the corresponding voltage value will be 4.6...4.8 Volts.

Operating principle and design of DBP

The absolute pressure sensor on Lanos determines the volume of air passing through the throttle valve. Depending on the amount of air passing and the load on the internal combustion engine, electrical impulses are created that are read by the ECU. Based on the magnitude of the pulses, the fuel-air mixture supplied to the cylinders is adjusted.

The absolute air pressure sensor has a vacuum chamber in its design. Due to this chamber, the pressure in the inlet fitting is compared and a corresponding signal is generated in the form of electrical pulses. The calculation of air pressure is carried out due to the following actions occurring inside the sensor:

1. The device is designed with a highly sensitive micromechanical diaphragm that deforms as the pressure on the intake manifold increases.
2. Depending on the amount of pressure, the diaphragm stretches. When it is stretched or deformed, the resistance changes on four strain gauges (variable resistor)
3. Depending on the resistance value of the strain gauges, voltage fluctuations occur in the circuit
4. The high sensitivity of strain gauges is ensured by the use of a silicon chip, so the varying voltage at the sensor terminals is from 1 to 4.9 V
5. Depending on the voltage that is supplied to the ECU and detected, a pulse is generated. This impulse is supplied to the injectors, thereby being responsible for preparing the mixture burned in the cylinders

This is interesting!
The higher the pressure indicator, the correspondingly higher the voltage value at the sensor terminals.

When the engine is not running, the pressure in the intake manifold will be the same as atmospheric pressure and amount to 101 kPa. It is at this moment that the sensor determines the amount of atmospheric pressure. When the engine starts, the throttle valve closes, which helps create a vacuum and create a pressure of about 30-33 kPa. With the damper open and the engine running, the pressure will be compared with atmospheric pressure and equal to 101 kPa. Pressure fluctuations occur when opening and closing the throttle valve.

From the principle of operation of the absolute pressure sensor on Chevrolet, Daewoo and ZAZ Lanos, it is clear that this element plays an important role in preparing the mixture. If the element operates with an error or does not function at all, the fuel assembly will be saturated and contribute to an increase in fuel consumption.

Checking the DBP sensor

Checking the absolute pressure sensor in the manifold comes down to the fact that you first need to make sure that it is clean, and therefore sensitive to changes in air flow, and then find out its resistance and the output voltage when the engine is running.

Cleaning the absolute pressure sensor

Please note that as a result of its operation, the absolute pressure sensor gradually becomes clogged with dirt, which blocks the normal operation of the membrane, which can cause partial failure of the DBP. Therefore, before checking the sensor, it must be removed and cleaned.

To clean, the sensor must be removed from its mounting location. Depending on the make and model of the vehicle, mounting methods and location will vary. Turbocharged engines typically have two MAP sensors, one in the intake manifold and one on the turbo. Typically the sensor is secured using one or two mounting bolts.

Cleaning the sensor must be done carefully, using special carb cleaners or similar cleaning agents. During the cleaning process, you need to clean its body, as well as the contacts. In this case, it is important not to damage the o-ring, contact elements of the housing and the membrane. You just need to spray a small amount of cleaning product inside and pour it back along with the dirt.

What is DTVV and why is it needed?

The intake air temperature sensor or IATV is an element responsible for determining the temperature readings of the air entering the cylinders. Many people confuse this element with the mass air flow sensor DMRV, which is not used on Lanos, Sens and Chances. The mass air flow sensor is not installed on Lanos, but to understand how this element differs from a temperature sensor, let’s look at their design and operating principle.

The TVB sensor is a flow meter that affects the operation of injection engines. Its main purpose is to analyze the temperature of the air entering the combustion chamber of the internal combustion engine. The temperature is determined by the voltage drop across the DTVV terminals. The ECU reads the voltage drop across the terminals, resulting in an adjustment and formation of the optimal amount of fuel-air mixture supplied to the cylinders.

A sensor malfunction will not lead to engine inoperability, but it will result in unstable operation and increased consumption. This is due to the fact that the control unit will receive incorrect readings of the intake air temperature, and at the same time will form the appropriate mixture composition. If the DTVV sensor is faulty, then the ECU uses the average readings of the flow meter (rough calculation), which corresponds to a value of 20 degrees. Based on this value, the appropriate composition of the mixture is prepared - enriched and lean.

Mass air flow sensor is not installed on Lanos, and instead a temperature sensor and DBP (absolute pressure sensor) are used. To understand how the DTVV differs from the DMRV, let’s consider the purpose of the second option. The mass air flow sensor, unlike the air flow sensor, is responsible for the values ​​of the quantitative composition or volume of air entering the cylinders. The sensor determines the amount of intake air and transmits a signal to the ECU. Depending on the amount of intake air, the composition of the fuel assembly is adjusted. The mass air flow sensor is installed on VAZs, but it is not used on Lanos. The mass air flow sensor has many disadvantages (the main one is its high cost), so Lanos, Sens and Chance are equipped with absolute pressure and intake air temperature sensors. These two devices replace the mass air flow sensor, which slowly counts air. To put it simply, the mass air flow sensor is an outdated model of the air meter, which today has been replaced by the air flow meter and the air pressure sensor.

Signs of a malfunctioning absolute pressure sensor. What should you pay attention to? »

Signs of a malfunctioning absolute pressure sensor. What should you pay attention to?

In old carburetor systems, its volume was regulated by air jets, an air damper and other devices. In modern engines, this function is performed by a sensor.

Symptoms of a malfunctioning absolute pressure sensor

will help the driver roughly determine the area for troubleshooting in the engine power system. This is important for any driver, since injection engines have several such devices, the problems of many of them are similar, so it is important to be able to correctly diagnose a broken engine.

The system of control and measuring instruments is designed to determine the mass composition of the fuel at a specific point in time, it sets the required ignition timing, and solves other issues of the optimal operating mode of the power unit. This product finds its use mainly on foreign cars, where it replaces, but there are also cars where these devices are installed together.

Very often in the conversations of “experienced” drivers it is called a vacuum sensor, since it measures air pressure relative to vacuum. A place for its installation is provided in the intake tract. While the throttle valve is closed while the engine is running, a small, or to be more precise, very low pressure of the air mixture is formed in the intake manifold.

To increase engine speed, the gas pedal is pressed, after which the throttle valve opens. The flow area of ​​the collector increases, the flow of the air mixture becomes greater, which means its pressure increases. Based on the data received from the absolute pressure sensor, the electronic control unit calculates the required amount of air mixture for the engine.

The industry produces two types of these devices: products made on the basis of thick-film technologies, and more modern and reliable designs of micromechanical technology. The first type of device is a variable resistor, in which the slider moves along the conductive layer, changing its resistance. With prolonged use, this layer wears out.

The second type of device is more reliable and progressive. It consists of four strain gauges, a silicon chip, and a diaphragm. The separation of air flow and vacuum occurs precisely with a diaphragm. A change in pressure leads to changes in the resistance of the strain gauges, as a result of which the voltage supplied to the control unit changes.

Recently, several modified designs of such devices have appeared. They provide for the installation of a special protective gel layer, which is exposed to the pressure of the air mixture. Information is sent from it to the electronic unit, and the advantage of such a device is that its service life increases several times.

You can guess about impending or existing problems with the absolute pressure sensor by some signs that appear during operation of the power unit. The most common “symptoms” of the disease are:

Noticeable increase in fuel consumption. The sensor signals to the control unit that the system is in complete order, but in fact it is very small. Because of this, the control unit directs almost only gasoline into the cylinders;

The dynamic performance of the car deteriorates, which does not disappear when the engine warms up;

When the engine is running, a very strong smell of fuel is felt in the exhaust pipe area;

On the engine in operating mode, even in the warm season, the exhaust of white smoke is visible;

When idling while the power unit is warming up, the engine speed does not drop for a long time;

When trying to change gears, the car jerks;

• Instability of the engine in any mode, the appearance of extraneous noise, often turning into a hum.

How to check DBP using computer diagnostics

Everything you need for independent computer diagnostics is presented in simple language in the Chevrolet Diagnostics section.

In this way, you can quite simply assess the condition of the sensor.

Here you need to pay attention to two parameters - barometric pressure and absolute pressure in the manifold. Why two?

Because DBP is not really DBP

It measures not only the absolute pressure in the manifold, but also the ambient pressure. This is necessary in order for the engine to operate adequately not only in ordinary terrain, but also, for example, in mountainous terrain, where atmospheric pressure decreases as altitude increases. And different atmospheric pressure has different effects on processes in the engine, so the ECU must know this same pressure in order to apply certain corrections in engine control. More details about the work of DBP and what processes affect its readings can be found here

We will touch on this parameter a little lower. Now let’s start checking DBP using diagnostic charts.

When the engine is not running, then the pressure in the manifold is equal to atmospheric pressure, which can be seen in the graphs

As we see, this is so. So at this stage everything is fine.

With the engine running and idling, the pressure in the intake manifold drops by almost 70% and should be 30-35 kPa

When you press the accelerator pedal, the pressure in the manifold inevitably increases. Therefore, DBP should signal this. If the damper is open to a large angle with the current load on the engine (acceleration, driving uphill, etc.), then the pressure in the manifold will increase to atmospheric

If the DBP, when pressing the accelerator pedal under load , practically does not change its readings or does so with a large delay, then you should definitely understand the reason for this behavior, since this is a malfunction. For example, if the engine speed under heavy load has already risen to more than 2000 rpm, but the DBP does not respond to this, showing low pressure in the manifold, then this is not normal.

Note: When you press the gas pedal at idle and there is no load on the engine (air conditioning, heated rear window, etc.), low readings (22-25 kPa) are adequate. That's how it should be! I'll try to explain it in simple language. When you press the gas pedal, a sharp surge in readings occurs - this is the DBP working to change the conditions in the manifold and the engine has not yet had time to spin up and “take in” the air that entered through the slightly open damper.

Then the engine gained speed and it is easy for it to rotate and develop further speed, since nothing interferes with it (no load). The higher its speed, the more it sucks air into itself, creating even greater vacuum in the manifold, since we do not open the damper completely, but only to maintain the speed we want.

Under load (we start, accelerate, turn on the air conditioner), the operating conditions change. It is no longer so easy for the engine to develop speed and it does so more slowly and does not have time to suck in the incoming air. Because of this, the pressure in the manifold increases. We press the pedal even harder, demanding revolutions from the engine, it strains and develops revolutions slowly. As a result, we open the damper completely and the pressure in the manifold becomes almost atmospheric. That is, the higher the pressure in the manifold, the heavier the engine. This is nothing more than an “engine load sensor”, and not a “sensor for calculating air mass”, which I wrote about above.

Here's another interesting point. Only here the DBP shows a very high barometric pressure, which in his opinion is as much as 112 kPa. Although a maximum pressure of 108 kPa was recorded on our planet!

Chevrolet Lanos absolute pressure sensor

For normal operation of the Chevrolet Lanos power plant, it is important what condition the absolute pressure sensor is in. When it fails, the engine begins to twitch, the car loses dynamics, and the environmental friendliness of the exhaust goes beyond acceptable standards.

Therefore, it is important to pay due attention to the sensor and, if it fails, promptly replace it.

Sensor location

The absolute pressure sensor is located in the engine compartment of the Lanos car. It is located on the front panel. In order to see the sensor, you will need to open the hood.

Methods for checking the absolute pressure sensor

You can check the absolute pressure sensor using a multimeter. To do this, you will need to connect the contacts to the probes and measure the voltage. At idle it should be about 1.3 V. When the vacuum changes, the device reading should change from 0 to 5 V.

Some car owners recommend checking DBP by disassembling it. In this case, it is possible to identify oxidized or damaged wires. The disadvantage of this method is the high risk of damage to the product during its opening.

How to check DBP yourself

To be completely honest, it is worth noting that the sensor has a mega reliable design and very rarely fails. But, unfortunately, I cannot say such flattering words about his wiring. At least on the Chevrolet Lacetti.

I don’t know where and from whom the idea came up to wire such an important sensor in this way. The fact is that two of the two sensor power wires have pins in their path, which over time can drain quite a bit of blood from the poor car owner.

Therefore, when checking DBP, it is necessary to pay more attention to the wiring and not to the sensor itself.

How can you check DBP?

There are many testing methods, but we only need the simplest ones and without special equipment. Right? I think yes!

Therefore, there are only two options left:

Required Tools

In order to mount a new absolute pressure sensor to replace the old one, you need to prepare the tools below.

Table - Tools that should be prepared to replace the absolute pressure sensor

In order to independently replace the absolute pressure sensor on a Chevrolet Lanos, it is recommended to use the step-by-step instructions below.

• Disconnect the negative terminal from the battery. This will de-energize the vehicle's on-board network.

• Disconnect the terminal block with the wiring harness.

• Disconnect the vacuum hose that goes to the absolute pressure sensor.

• Unscrew the two nuts securing the sensor. It is important to keep the bolts from turning.

Some car owners dismantle the sensor assembly with the bracket. This action is relevant if the fastenings of the meter have become sour and cannot be loosened.

• Reassemble everything in the reverse order of removal.
• Test run the power unit and check its operation.

Some car owners upgrade the device for better performance of the DBP. The sensor is disassembled and the wiring is soldered if necessary. After this, the entire void in the case is filled with silicone sealant. According to driver reviews, this action has the best effect on the stability of the engine.

Sensors responsible for the operation of the internal combustion engine

Let's analyze the most frequently failing sensors responsible for the operation of the internal combustion engine, consider the causes of breakdowns and figure out where these ill-fated sensors are located.

So, internal combustion engine sensors that often fail include the following:

• idle speed sensor (IAC);
• throttle valve sensor (TPS);
• camshaft sensor;
• speed sensor;
• knock sensor;
• fuel sensor;
• mass air flow sensor (MAF);
• catalyst sensor;
• Lambda probe.

The idle speed sensor is often confused with the TPS, but their purposes are somewhat different, and they are installed side by side. The DRXX is installed under the throttle, to find it you need to remove the pipe going from the air filter to the throttle, there is a DRXX under it, remove the connector from the DRXX, unscrew the 3 bolts, and remove the DRXX from the throttle body. The main difference from the TPS is the 3-bolt fastening.

The throttle position sensor is located a little deeper - on the side of the throttle assembly; to find it, you need to remove the pipe with the air filter, then unscrew the 4 screws securing the throttle valve to the intake manifold. After which we will gain access to the bracket on which this sensor is installed. We remove the corrugated wiring from the connector of this sensor, unscrew the 2 fastening screws, and then remove it.

The main difference from the DRXX is the 2-bolt fastening.

The camshaft position sensor is located on the rear side of the cylinder head cover. It is difficult to confuse it with anything else; the pictures show the process of removing this sensor. To remove it, you need to disconnect the “braid” of wires and unscrew the fastening bolt, after which you can safely pull out the sensor.

The vehicle speed sensor is located on the top of the transmission housing. To remove this sensor, remove the wiring connector from the block by first pressing out the metal lock. After that, the fastenings of the sensor itself are unscrewed and it is successfully pulled out.

The knock sensor is located at the top of the cylinder block on the right side; to remove it you only need one “24” key.

The air sensor, also known as the mass air flow sensor (MAF), is located between the throttle valve and the air filter; it looks like a plastic insert with an o-ring, inside which the sensor itself is located. To remove and replace it, you must have a screwdriver suitable for T20 or T25 size screws, depending on the model and year of manufacture of the car.

To remove the sensor, remove the terminal from it, unscrew one or two screws (depending on the model and year of manufacture of the car), after which the housing with the sensor assembly is carefully pulled out.

The fuel sensor (MR503462), like all other cars, is located directly in the gas tank on the Lancer. To access this sensor, you need to remove the rear seat, gaining access to the technical “hatch”. The hatch is tightly seated on the sealant, so after removing it and performing all the necessary work, you will need to secure it again to the sealant. So, we remove the hatch, we see another cover and a connector located on it.

We disconnect the connector, unscrew the 6 screws and begin to remove the fuel pump, since the sensor is located on it. The sensor looks like a textolite plate on which metal tracks are applied along which the float contact slides. The fuel level float and sensor are inextricably linked and are one whole.

The catalyst sensor is located in the exhaust manifold; it can be detected if you “walk” from the engine exhaust tract to the place where the pipes join together. This is where this sensor is located. To remove it, you need to remove the thermal insulation casing from the engine, then disconnect the sensor connector and unscrew the sensor using a “22” key.

The lambda probe is also located on the exhaust tract (outside), near the front passenger's feet. The removal algorithm is absolutely the same - we “go” along the wire from the sensor, find the connector and disconnect it, then use the “22” key to unscrew the sensor.

The lambda probe is also located on the exhaust tract (outside), near the front passenger's feet. The removal algorithm is absolutely the same - we “go” along the wire from the sensor, find the connector and disconnect it, then use the “22” key to unscrew the sensor.

Answer: Diagnostics of DBP on Lanos

If I’m not sure about the diagnostics, then I additionally do this: I connect the DBP, a mechanical vacuum gauge and a 200 ml medical syringe through a tee. (to create a vacuum artificially). I attach a multimeter between the signal wire and the negative wire to the sensor (do not remove the connector), turn the ignition on, create a vacuum with a syringe and observe the change in voltage on the signal wire. I smoothly draw up the vacuum, and the voltage smoothly changes from 4.5V to 1V. Somewhere on the Internet I found a table of the dependence of voltage on vacuum on a Daewoo.

Answer: Diagnostics of DBP on Lanos

And you, dear one, wouldn’t tell who and what to do, but it would be better to help with advice. So diagnostics: - actually reading the error code - remove the vacuum tube with the engine running - if there are no interruptions in the engine’s operation, then it (DBP) is dead - with the engine not running engine, remove the block from it and, turning on the ignition, check the voltage in the block at outputs A and C with a voltmeter - it should be 5.0 +-0.2V. Then turn off the ignition, remove the cover from the block by squeezing the latches and in this form connect the block to the sensor. Start the engine, and by sliding the probes from below to the block, measure the voltage at output B and vehicle ground - at idle it should be 1.3+-0.4V.

Re: Diagnostics of DBP on Lanos

First of all, I recommend checking the voltage between the two outer contacts of the MAP, it should be 5 V. Then check the voltage between the first and second (middle) contacts, with the throttle closed it should be more than 4 V. And if you start the engine, then at idle speed at when the engine is warm, it should be less than 2 V. It is better to measure the voltage using three short bare wires inserted into the MAP block.

“Low pressure in the intake manifold” is the main error diagnosed by the ECU when the MAP is faulty. Most likely the sensor is marked 14.3814 These sensors are afraid of water. Basically, this malfunction appears after washing the engine, after 2 weeks.

Re: Diagnostics of DBP on Lanos

First of all, I recommend checking the voltage between the two outer contacts of the MAP, it should be 5 V. Then check the voltage between the first and second (middle) contacts, with the throttle closed it should be more than 4 V. And if you start the engine, then at idle speed at when the engine is warm, it should be less than 2 V. It is better to measure the voltage using three short bare wires inserted into the MAP block.

“Low pressure in the intake manifold” is the main error diagnosed by the ECU when the MAP is faulty. Most likely the sensor is marked 14.3814 These sensors are afraid of water. Basically, this malfunction appears after washing the engine, after 2 weeks.

• Forum
• Automotive electronics
• Electronics Diagnostics
• General diagnostic issues, theory
• Diagnostics of DBP on Lanos

Topic information