To ensure the stable operation of the engine of a modern car, a wide variety of sensors are used that collect information about the operation of a particular system. Based on their data, the electronic control unit adjusts the quality of the fuel mixture, adjusts its amount for entering the combustion chambers, determines the desired ignition timing, turns on and off various additional mechanisms.
In this article we will talk about what the VAZ-2114 oxygen sensor (lambda probe) is , consider its design and principle of operation. In addition, we will try to understand the malfunctions of this element and methods for their elimination.
What is an oxygen sensor
An oxygen sensor is an electromechanical device designed to determine the quantitative oxygen content in exhaust gases. Its use is mandatory for all cars with a class of environmental friendliness above "Euro-2".
Why is it needed? The fact is that modern environmental standards require the car to have a minimum content of harmful compounds in the exhaust. To achieve their reduction is possible only through the formation of an ideal (stoichiometric) fuel mixture. It is for these purposes that the oxygen sensor, or, as it is also called, the lambda probe, serves. The electronic control unit, having received information about the oxygen content in the exhaust, increases or decreases the amount of air to form a mixture.
Where is the oxygen sensor
In VAZ-2114 vehicles, the lambda probe can be located in different places, depending on the engine modification. In the "fourteenth", equipped with one and a half liter power units, it is located on top of the exhaust pipe. You can get to it only from below, having driven the car into a viewing hole or overpass. The 1.6-liter VAZ-2114 lambda probe is much more convenient. It is screwed into the upper part of the exhaust manifold housing. You will immediately see it by lifting the hood.
How is the oxygen sensor
The VAZ-2114 lambda probe has a fairly simple design. It is based on a ceramic element with two electrodes. They are usually coated with zirconia. One of the electrodes is in contact with air (removed from the exhaust communications), and the second with exhaust gases.
The principle of operation of the device is based on the potential difference that occurs between the contacts of the device during engine operation. The electronic control unit sends an electric pulse to the sensor and analyzes its changes. Based on the increase or decrease in voltage at the probe contacts, the ECU “makes a conclusion” about the amount of oxygen in the exhaust.
Lambda probe: symptoms of a malfunction (VAZ-2114)
The failure of the “fourteenth” oxygen sensor is usually accompanied by the following symptoms:
- “CHECK” signal lamp on the instrument panel warning the driver about an error;
- the engine idling is unstable (the speed is floating, the motor stalls periodically);
- a noticeable decrease in power and traction characteristics of the power unit;
- the car “jerks” when picking up speed;
- increase in fuel consumption;
- excess levels of toxic substances in exhaust gases (determined by measurement at a specialized station).
What can the electronic control unit tell?
If a signal lamp on the dashboard lights up, notifying of errors in the engine, and its burning is accompanied by the above problems, it is advisable to test the controller. Today, this can be done both at the service station and at home. Of course, if you have a special tester and laptop (tablet, smartphone) with the appropriate software. When connected, this device will give you codes of possible problems.
For VAZ-2114 vehicles, a lambda probe that malfunctions can report its malfunction with the following errors:
- P0130 - wrong sensor signal;
- P0131 - Excessive excess oxygen levels in exhaust fumes;
- P0132 - Too low oxygen content;
- P0133 - weak or slow sensor signal;
- P0134 - lack of sensor signal.
What can happen to the lambda probe
The lambda probe resource for the “fourteenth” declared by the manufacturer is 80 thousand kilometers. But this does not mean at all that he cannot fail much earlier or serve twice as long.
The cause of the malfunction of the lambda probe VAZ-2114 may be:
- overheating of the working element;
- violation of the tightness of the connection of the sensor with the housing of the exhaust manifold;
- clogged device contacts due to the use of low-quality fuel, or the ingress of oil (coolant) into gasoline.
Procedure for problems with the lambda probe
If you find signs of an oxygen sensor failure, do not rush to the store to get a new device. Replacing the VAZ-2114 lambda probe is not such a cheap pleasure. The fact is that this sensor costs about 2.5 thousand rubles. Therefore, you must first:
- visually inspect the lambda probe;
- establish its modification (in case of acquisition of a new and subsequent replacement);
- check the functionality of the probe.
Which lambda probe on the VAZ-2114
On the first Samar models of the fourteenth model with one and a half liter engines, Bosch sensors 0 258 005 133. were installed. This lambda probe ensured the operation of the power unit in accordance with the requirements of Euro-2 standards.
Since 2004, VAZ-2114 engines began to be equipped with Bosch sensors 0 258 006 537. They differ from the previous modification by the presence of a heating element. It is noteworthy that all Bosch oxygen sensors for the “fourteenth” are interchangeable.
We check the performance of the oxygen sensor with our own hands
How to check the lambda probe on the VAZ-2114 for performance? Complete device diagnostics can only be done using an oscilloscope. But to determine whether he is working or not, it is possible without complex electronics. To do this, you only need a voltmeter. Connect its “negative” probe to ground, and the “positive” to pin “B” in the sensor connector without disconnecting it from the on-board network. Turn on the ignition and look at the voltmeter. The voltage at the terminals of the device must match the voltage of the battery. If it is smaller, then an open circuit is possible in the sensor circuit.
If everything is OK with the voltage, check the sensitivity of the working element of the probe. To do this, connect the "negative" probe of the voltmeter to the "C" terminal of the sensor, and the "positive" one to pin "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.
Repair or replacement
Having determined that the “fourteenth” lambda probe is faulty, you can either try to repair it, or simply replace it. Restoring the sensor consists in cleaning its contacts from soot. It may be the reason that the device has ceased to function normally.
First, the sensor must be unscrewed from the collector or front pipe. This is not always easy to do. The fact is that its body very often sticks to these elements of the exhaust system. In this case, anti-rust fluid (WD-40 or equivalent) may help. Treat the junction with such a liquid and wait half an hour.
When the sensor is unscrewed, pay attention to its body. He is not separable. The contacts that we have to clean are located behind the slots of the case in its lower part.
Important: do not clean the contacts mechanically (with a knife, sandpaper, file, etc.)! So you only exacerbate the situation and permanently disable the sensor.
Contacts should only be cleaned with chemicals. For example, phosphoric acid. Just place the bottom of the probe in acid for half an hour, and then dry on a gas burner.
It is not necessary to disassemble the sensor, sawing its body. As practice shows, after such a procedure, its performance is no longer returned.
If you decide to replace the lambda probe, buy a new device that meets the specifications in the car shop and install it in place of the old one. After switching on the ignition, start the engine, warm it up and check if the “CHECK” warning light is on.
Methods of cheating electronic control unit
There are three more ways to restore engine performance without buying a new oxygen sensor. Without a doubt, they were invented by our craftsmen. And they consist in the fact that it is necessary to mislead the electronic control unit so that it does not notice errors in the operation of the sensor.
The first method is mechanical. For its implementation, a special spacer (sleeve) is screwed between the lambda probe and the collector body (front pipe). Its use allows you to distance the sensor contacts from the exhaust gases. Thus, the amount of oxygen between them artificially increases, and the electronic control unit "remains satisfied" with the result.
There is a similar blende lambda probe VAZ 2114 about 500 rubles. And if you have a lathe, you can make it yourself.
The next way to trick the computer is electronic. Its essence is to install a primitive converter in the sensor circuit, consisting of one resistor (1 MΩ) soldered into the gap of the blue wire of the connector and one capacitor (1 μF) connected between the blue and white wire. As a result of such a simple deception, the electronic control unit will constantly receive the signal of the desired voltage, and perceive the operation of the lambda probe as appropriate.
Alternatively, you can still reflash the controller by changing its software. But to entrust such manipulations with the engine brain is better for specialists.
How to extend the life of a lambda probe
To keep the oxygen sensor as long as possible, do not neglect the following tips:
- use only high-quality fuel;
- do not allow oil and other process fluids to get into the fuel;
- monitor the operating temperature of the engine, do not allow it to overheat;
- Diagnose the oxygen sensor in accordance with the schedule of scheduled maintenance provided by the manufacturer;
- when identifying signs that indicate problems with the lambda probe, do not delay with the diagnosis.