What is an oxygen sensor? How to check the lambda probe VAZ

30.05.2013

Oxygen sensor

The oxygen sensor (OS) is installed on injection VAZs (except for the first models with a Bosch 1.5.4 controller).

This is an integral part of the engine power system. This sensor is designed to assess the condition of the exhaust (the presence of oxygen in the exhaust). In other words, based on the amount of oxygen in the exhaust, it regulates the working mixture.

DC also has a second, but no less popular name: “lambda probe”. That is, it is one and the same.

Operating principle of DC (lambda probe)

The working surface of the sensor is a ceramic material coated with platinum.

The operating temperature of the surface is 350 degrees Celsius and above. Therefore, before heating the lambda probe, during the first 5 minutes after starting the engine, the working mixture is adjusted according to the readings of other sensors in the engine power system. To speed up the heating of the part to operating temperature, an electric heater is installed in it.

The principle of operation is as follows: exhaust gases cover the working surface of the lambda probe, which in turn reacts to the difference in oxygen levels in the exhaust gases and the environment. It then sends a signal to the ECU, which adjusts the fuel mixture.

How is self-diagnosis performed?

Press the button to start diagnostics

We have sorted out the main errors on the Priora, now it’s worth finding out how self-diagnosis is performed. The VAZ 2170 with 16 valves has a special controller with which diagnostics are performed. If you have an on-board computer installed, then diagnostics are performed on it. There is also special equipment that allows for a more in-depth check of Priora 16 class systems.

Since most Priora 16 cars already have an on-board computer, we will consider the option without the use of special devices. Diagnostics begins with activation of the test mode. The work proceeds according to the following scheme:

1. Turn off the ignition. Now we hold down the daily mileage reset button, without releasing the button, we start the ignition of the Priora 16 cl;
2. On the instrument panel you will see a display with an indication. After turning on the ignition, all components of the instrument panel will light up. The needles of the temperature, speedometer, tachometer and other instruments will begin to move to the maximum level and back. This behavior indicates that self-diagnosis has begun;
3. Let's move on to the right steering wheel switch. Here you will find a button for switching the on-board computer settings. Click on it, a message with the software version will appear on the instrument panel screen;
4. The instrument panel error diagnosis will begin if you press this key again. Various codes will appear on the display, which you can decipher in the table below;
5. When the diagnostics are complete, you can reset the error data. Press and hold the daily mileage reset button for about 5 seconds.

Where is the oxygen sensor (lambda probe) located?

For 1.5 l engine

The lambda probe (number 11) is installed in the exhaust system on the exhaust pipe. Screwed in from above, in front of the resonator or spacer (if there is no resonator). In other words: put the car in a pit and look throughout the exhaust system for a sensor sticking up. DC is the only sensor that is installed in the exhaust system, so you won’t miss it.

Exhaust system for 1.5l engine

For 1.6L engine

The exhaust system of this engine is slightly different from the 1.5 liter. Pay attention to the figure: In this exhaust system, 2 DCs are planned (at number 2) - both are located on the catalytic collector. These engines are equipped with both 1 and 2 oxygen concentration sensors: Euro-2 toxicity standard - 1 DC, Euro-3 - 2 DC.

Exhaust system for 1.6l engine

We check the performance of the oxygen sensor with our own hands

How to check the lambda probe on a VAZ-2114 for functionality? Full diagnostics of the device can only be done using an oscilloscope. But it is possible to determine whether it is working or not without complex electronics. To do this, you only need a voltmeter. Connect its “negative” probe to ground, and the “positive” probe to terminal “B” in the sensor connector, without disconnecting it from the on-board network. Turn on the ignition and look at the voltmeter reading. The voltage at the device terminals must match the battery voltage. If it is less, it means there may be a break in the sensor circuit.

If the voltage is okay, check the sensitivity of the working element of the probe. To do this, connect the “negative” probe of the volt sensor, and the “positive” probe to contact “A”. The voltage should be within 0.45 V. If this indicator is exceeded by more than 0.02 V, the sensor must be replaced.

Signs of DC malfunction

1. High gasoline consumption (from 12 liters or more). But this problem can also occur for other reasons (Causes of high fuel consumption)
2. Unstable idle. Also, the causes of this malfunction may be: dead IAC, mass air flow sensor, air metering sensor, etc.
3. Dips during acceleration, drop in engine dynamics and power. Also, the reasons for low dynamics can be faults in the following elements: , , , low compression, etc.

Useful articles:

• How to check DC?
• How to repair a recreation center?

What problems to expect in the event of a breakdown?

Of course, certain symptoms begin to appear immediately. For the oxygen sensor on the VAZ 2107, as well as on other cars in which an injector is installed, this is expressed very specifically. The saddest thing for the driver is an increase (and a significant one) in fuel consumption. The car begins to “eat” gasoline with a very good appetite. The movement also occurs with jerks, as if the engine is “troubling” or sometimes it does not have enough air.

Consequently, engine performance deteriorates and the crankshaft speed may even fluctuate. In this case, the catalytic converter stops working in normal mode, therefore, in this case, you cannot even mention that your VAZ 2107 car meets any Euro standards. Because when testing exhaust toxicity, you will get very high CO levels.

Source

DK errors

You can detect the presence of these errors by the yellow light on the check engine panel coming on (or it may not light up). You can read these errors either using the on-board computer or using computer diagnostics.

Most often, errors associated with DC appear due to a malfunction of the heating circuit, as a result of which the sensor gives incorrect parameters.

In this case, you need to look for a broken wire or replace the sensor.

Replacement

It is not difficult to replace the DTOZH with your own hands on an injection VAZ 2109. Follow the step-by-step instructions to resolve any issues that may arise.

Removing the device

1. First of all, check the condition of the fuses. It is not uncommon for them to burn out, which causes a failure of the coolant temperature sensor.
2. Wait until the car has cooled down completely. Under no circumstances should you replace the DTOZH on a hot engine.
3. Disconnect the wires going to your DTOZH. You just need to do this in a situation where, when you turn on the ignition, the temperature indicator needle begins to rise sharply and sometimes reaches the maximum level.
4. If no changes occur with the arrow, the fault is not with the sensor itself, but with the wire going to it.
5. If the needle starts to drop when you turn on the ignition, the coolant temperature sensor has failed and needs to be replaced.
6. There is no need to remove half of the units to get to the DTOZH. Access to the device is free, there should be no problems.
7. Drain the coolant from the system. This is an excellent reason to at the same time change the antifreeze for a new one, if necessary. If the coolant is fresh, use a clean container to drain it.
8. Disconnect the wiring from the sensor.
9. Using a socket, unscrew the regulator so that it can be easily removed by hand.
10. Clean the device landing area. This usually accumulates a decent amount of dirt and dust, which can cause the new antifreeze temperature sensor to not work correctly.
11. To clean, use any rag that does not leave behind lint or threads.
12. Treat the nest with a degreaser.
13. Insert the new regulator. The mistake of many is that, supposedly to increase the reliability of the installation, they seal the sensor with sealant. You shouldn’t do this, because this way the DTOZH can only work worse.
14. Replace the power cord. Only if the check shows that it has a break or is damaged, it is better to replace the wire immediately. We do not recommend repairing it with electrical tape.
15. Pour coolant back into the system. Even if you changed the coolant a couple of months ago, it is better to replace it with a fresh one at the same time. It definitely won't get any worse.
16. Start the engine and check the operation of the new TOZ sensor.

Replacing the DTOZ yourself is a fairly simple process. You don’t have to spend money on car service services, plus you’ll get the necessary experience in car repairs yourself.

Each injection system (and the VAZ 2109 is no exception) has a set of sensors (controllers) to receive information about the operating mode of the engine and regulate its operation. There are several systems with different sensors, so as not to get confused we will look at all existing controllers. When problems appear with the injector, this means that the engine sensor on the VAZ 2109 is acting up, and maybe more than one. Our article will help you understand their location, signs of malfunction, and tell you how to replace any of them yourself.

Why does the lambda probe die?

We have already clarified above that the service life of the oxygen sensor is 80-160 thousand km. You probably have a question: why is there such a spread in the resource, as much as 80 thousand km? In fact, it depends on the conditions in which the car was operated:

1. Bad gasoline, the exhaust of which contains a lot of lead and iron, clogs the sensor electrodes after several fill-ups.
2. Poor condition of oil scraper rings and caps. Because of them, oil can get into the mixture, and with it into the exhaust system.
3. Due to clamped valves, pops are released into the exhaust system, which destroy the working surface of the sensor.
4. Due to an incorrect mixture, ignition timing, as a result of which the sensor overheats, crackling from the high temperature of the converter or catalyst.

Reasons for reducing the service life of equipment

• Violation of vehicle operating conditions, failure to comply with scheduled technical inspection deadlines;
• Filling the car with low-quality fuel;
• Purchase and subsequent installation of non-original parts;
• Violation of installation technology;
• Defective parts during manufacturing;
• Damage due to an accident, collision, impact;
• Incorrect operation of the firmware of the electronic control unit.

CO – potentiometer

SO – potentiometer VAZ

Idle speed controller

The idle speed control adjusts the crankshaft speed at idle by controlling the amount of supply air that bypasses the throttle valve (the throttle valve is closed). Principle of operation:

• It consists of a two-pole stepper motor and a cone valve connected to it
• The valve is extended or retracted by computer signals
• When the regulator needle extends completely (this corresponds to 0 steps), it blocks the air supply
• And when the needle is retracted, it provides air access proportional to the number of steps the needle is indented from the saddle
• Failure leads to instability of idle speed, and the engine may stall

Replacing the regulator goes like this:

• De-energize the car wiring by removing the terminals from the battery
• Press the plastic latch to disconnect the connector from the regulator located on the throttle pipe and marked with number 2

Number 2 indicates idle speed control

Idle speed regulator VAZ

• Check the condition and replace, if necessary, a torn or lost elasticity sealing ring of the regulator

Warning: Do not try to pull out or push in the valve with your hands, this may damage the idle speed control. To do this, you need to use a diagnostic device or a special monitor.

• We install a new sensor on the car, lubricate its O-ring with engine oil, and do not forget to connect the connector to it

Here we looked at the VAZ 2109 injector; the sensors on the engine may be different, depending on the model, but there is an air conditioner sensor located on the dashboard.

Recommendations for the selection of parts and components

For domestic car brands, service station technicians advise purchasing Russian-made parts, since their cost is 10-15% cheaper compared to foreign analogues. At the same time, the workmanship is identical.

Before purchasing, always check the catalog numbers with the actual data specified in the operating instructions for the technical product.

Use the services of certified service stations for prevention, diagnosis and replacement of faulty equipment.

List of online stores selling parts (Moscow, St. Petersburg, Kyiv regions)