How to change the coolant temperature sensor on a VAZ 2106

Any driver should know the temperature of the engine of his car. This also applies to the owners of the VAZ 2106. Lack of awareness of the critical temperature of the engine can result in its overheating and jamming. The temperature of the engine on the VAZ 2106 is monitored by a special sensor. It, like any other device, sometimes fails. Fortunately, it is quite possible to change the temperature sensor yourself. Let's figure out how it's done.

What is a temperature sensor for?

The main function of the "six" temperature sensor is to control the heating of antifreeze in the engine and display information on the car's dashboard. However, the functions of such sensors are not limited to this.

The sensor is responsible not only for the temperature of the engine, but also for the quality of the fuel mixture

In addition, the sensor is connected to the car control unit. Motor temperature data is also transmitted there. And the block, in turn, depending on the received temperature, makes corrections when supplying the fuel mixture to the engine. For example, if the engine is cold, then the control unit, based on the data obtained earlier, will set an enriched fuel mixture. This will make it easier for the driver to start the car. And when the engine warms up, the control unit will make the mixture leaner so that the car does not suddenly stall. That is, not only the driver's awareness of the state of the engine, but also fuel consumption depends on the correct operation of the antifreeze sensor.

How does the temperature sensor work on the VAZ 2106

The main element of the sensor is a thermistor. Depending on the temperature, the resistance of the thermistor may change. The thermistor is installed in a sealed brass housing. Outside, the contacts of the resistor are brought out to the case. In addition, the case has a thread that allows you to screw the sensor into a regular socket. There are two contacts on the sensor. The first is connected to the electronic unit of the car. The second - to the so-called mass.

The main element of the sensor is a resistor

For the thermistor in the sensor to work, a voltage of five volts must be applied to it. It is supplied from the electronic unit. And voltage stability is ensured by a separate resistor in the electronic unit. This resistor has a constant resistance. As soon as the temperature of the antifreeze in the engine rises, the resistance of the thermistor begins to drop.

The sensor is connected to ground and to the coil of the measuring device

The voltage applied to the thermistor also drops sharply. Having fixed the voltage drop, the control unit calculates the temperature of the motor and displays the resulting figure on the dashboard.

Where is the temperature sensor

On the VAZ 2106, temperature sensors are almost always installed in nests on the cylinder blocks.

The temperature sensor on the "six" is usually installed in the cylinder block

In later models of the "sixes" there are sensors installed in thermostat housings, but this is a rarity.

In later models of "sixes" temperature sensors can also be on thermostats

This sensor on almost all machines is located next to the pipe through which hot antifreeze goes into the radiator. This arrangement allows you to take the most accurate temperature readings.

Signs of a broken sensor

It is generally accepted that the temperature sensor on the VAZ 2106 is a reliable device, since its design is very simple. However, problems may occur. As a rule, all problems are associated with a change in the resistance of the thermistor. Due to the changed resistance, the operation of the electronic unit is disrupted, which receives erroneous data and cannot correctly affect the preparation of the fuel mixture. You can understand that the sensor is faulty by the following signs:

• severe oxidation of the sensor housing. As mentioned above, usually the sensor housings are made of brass. It is a copper based alloy. If the driver, having unscrewed the sensor from the socket, found a green coating on it, then the cause of the breakdown was found;
  

  A green oxide film indicates a broken temperature sensor.
• significant increase in fuel consumption. If the sensor resistance has changed, the control unit may overestimate the fuel consumption, although there are no real reasons for this;
• abnormal engine behavior. It is difficult to start it even in the warm season, it suddenly stalls, and at idle it is extremely unstable. The first thing to do in such a situation is to check the antifreeze sensor.

With all of the above problems, the driver will have to change the temperature sensor. It is beyond repair, so going to an auto parts store and replacing the unit is the only viable option. The price of sensors for the VAZ 2106 starts at 200 rubles.

Methods for checking temperature sensors

If the driver wants to make sure that the antifreeze sensor is the cause of the problems with the car, then you will have to carry out a simple verification procedure. But before proceeding with it, you need to make sure the integrity of the automotive wiring. As mentioned above, in order for the sensor to work normally, a voltage of 5 volts must be continuously applied to it. To make sure that the applied voltage does not deviate from this value, you should start the car, and then remove the wires from the sensor and connect them to the multimeter. If the device clearly shows 5 volts, then there are no problems with the wiring and you can proceed to examine the sensor itself. There are two verification methods. Let's list them.

Hot water test

The sequence of actions in this option is simple.

1. The sensor is placed in a pot of cold water. An electronic thermometer is also lowered there (it is much more convenient than usual, because the measured temperatures will be quite high).
   

   The thermometer and sensor are placed in a container of water
2. A multimeter is connected to the sensor (it should be switched so that it measures resistance).
3. A pan with a sensor and a thermometer is installed on a gas stove.
4. As the water heats up, the readings of the thermometer and the corresponding resistance values ​​\uXNUMXb\uXNUMXbgiven by the multimeter are recorded. Readings are recorded every five degrees.
5. The values ​​obtained should be compared with the figures given in the table below.
6. If the readings obtained during the test deviate from the tabular ones by more than 10%, then the sensor is faulty and needs to be replaced.

Table: temperatures and their corresponding resistances, characteristic of serviceable VAZ 2106 sensors

Temperature ° C	Resistance, Ohm
+5	7280
+10	5670
+15	4450
+20	3520
+25	2796
+30	2238
+40	1459
+45	1188
+50	973
+60	667
+70	467
+80	332
+90	241
+100	177

Test without electronic thermometer

This method of checking the sensor is simpler than the previous one, but less accurate. It is based on the fact that the temperature of boiling water reaches one hundred degrees and does not rise higher. Therefore, this temperature can be used as a reference point and find out what the resistance of the sensor will be at one hundred degrees. The sensor is connected to a multimeter switched to the resistance measurement mode, and then immersed in boiling water. However, you should not expect that the multimeter will show a resistance of 177 ohms, which corresponds to a temperature of one hundred degrees. The fact is that the temperature of water during the boiling process is constantly decreasing and averages 94-96 ° C. Therefore, the resistance on the multimeter will vary from 195 to 210 ohms. And if the numbers given by the multimeter differ from the above by more than 10%, the sensor is faulty and it's time to change it.

Replacing the antifreeze temperature sensor on a VAZ 2106

Before changing the antifreeze sensor to the VAZ 2106, several important nuances should be taken into account:

• the car engine must be cold. After unscrewing the sensor, antifreeze begins to flow out of its socket. And if the engine is hot, then the antifreeze does not flow out of it, but is thrown out in a powerful jet, since the pressure in a hot engine is very high. As a result, you can get severe burns;
• Before buying a new sensor in the store, you should carefully examine the markings of the old one. Almost all VAZ classics use the same sensor marked TM-106. You should purchase it, since the correct operation of other sensors is not guaranteed by the manufacturer;
• before replacing the sensor, both terminals must be removed from the battery. This will avoid a short circuit, which is possible when antifreeze flows out and this liquid gets on the wires.

Now about the tools. We will only need two things:

• open-end wrench for 21;
• new antifreeze sensor on VAZ 2106.

Sequencing

Replacing the sensor consists of two simple steps:

1. The protective plastic cap with wires is carefully removed from the sensor. After that, the sensor is unscrewed a few turns with a key of 21.
   

   Having unscrewed the sensor, the hole must be quickly closed with a finger
2. When literally a couple of turns remain until the sensor is completely unscrewed, you should put the key aside and take a new sensor in your right hand. With the left hand, the old sensor is completely unscrewed, and the hole in which it stood is plugged with a finger. The new sensor is brought to the hole, the finger is removed, and the sensor is screwed into the socket. All this must be done very quickly so that as little antifreeze as possible flows out.

The operating instructions for the VAZ 2106 require that the coolant be completely drained from the machine before replacing the sensor. The vast majority of drivers do not do this, rightly believing that it is not worth changing all the antifreeze because of such a trifle as a sensor. It's easier to change the sensor without any drains. And if a lot of antifreeze has leaked out, you can always add it to the expansion tank.

Video: changing the antifreeze sensor on the "classic"

Temperature sensor replacement!

So, replacing the antifreeze temperature sensor is a task that even a novice motorist is quite capable of. The main thing is not to forget to cool the car engine well, and then act as quickly as possible. And everything will work out.