Coolant temperature sensor VAZ 2114: Malfunctions, Replacement

Many motorists have encountered the fact that the temperature indicator arrow on the VAZ-2114 dashboard stopped showing, did not move from the zero position, or froze. But not everyone understands what causes this malfunction and how to fix it. In this article, we will consider possible options for the occurrence of such a breakdown and methods of elimination.

Video about diagnosing the temperature gauge (problem overview):

The video will tell you how to check and find the reason for the temperature gauge needle hanging up.

Sensor design

The sensor is a thermoelement placed in a bronze shell. It has direct contact with antifreeze, and the thermoelement, which is enclosed in the sensor, changes its resistance as the temperature rises or falls and transmits the received readings to the computer.

The sensor has a threaded connection sealed with a special copper ring; on the top of the sensor there is a connector for connecting a plug.

Coolant temperature sensor VAZ 2114

Is the engine overheating because the fan does not turn on in time? The coolant temperature gauge shows that it has not yet warmed up enough, and the fan has already turned on? Or, on the contrary, does the indicator indicate that the fluid is at a high temperature, but the fan does not turn on and the engine does not overheat? Then the coolant temperature sensor of the BAZ 2114 is to blame.

You just need to differentiate:

Coolant temperature indicator sensor (CLT). It goes to the instrument panel and shows us how many degrees the coolant is currently at;
Coolant temperature sensor (CLT). It also measures the degree of heating, but sends the data not to the instrument panel, but to the ECU, which determines whether the fan should be turned on or not.

If the engine overheats because the fan does not turn on in time, then most likely the reason is the temperature sensor. And if the situation is the same as in the second and third questions, then there is a high probability that this is due to a faulty pointer sensor.

They are united by only two things:

they are removed and installed in the same way, only different keys are needed to open them - for the one that provides information to the ECU, you will need the 19th key, for the second - the 21st.
are equally checked for functionality.

Therefore, today you will learn how to remove and install this part, and also how to check if it works.

Temperature sensors

To measure the fluid temperature, two sensors are used, one of them is directly connected to the ECU, and the other to the dashboard. Let's look at each sensor separately.

DTOZH for ECU

This sensor is used only for working with the engine control unit. Measuring the liquid temperature readings, it transmits them to the ECU and, based on the data received, the unit adjusts the air-fuel mixture and also turns on the cooling fan when the liquid temperature reaches a high temperature.

The DTOZH is located in the thermostat housing on a threaded connection.

DTOZH for the dashboard

This sensor is not involved in any operation of the internal combustion engine, but is only informative. This DTOZH is connected to the instrument panel, namely to the liquid temperature scale and measures it only to inform the driver about the state of the internal combustion engine cooling system.

The DTOZH is located in the cylinder head through a threaded connection.

The main causes of DTOZh breakdowns

There are several possible reasons why this sensor may stop working. Namely:

there is no contact with the sensor;
damage to wire insulation or broken contacts;
systemically inoperative fan;
complete failure of the device.

Symptoms of a malfunction in the DTOZH are:

the car engine has not yet warmed up to its normal state, but the fan is already running;
a well-warmed engine refuses to work;
Gasoline consumption has increased significantly.

Remember, before you start checking the coolant temperature sensor, you need to make sure of its location.

This is done so as not to accidentally confuse this part with the coolant temperature indicator sensor.

Sensor check

The sensors are checked after its dismantling. To carry out diagnostics, you must have a thermometer and a multimeter.

Let's start checking

It is necessary to boil water and immerse the thermometer in it.
Next, set the switch on the device to measure resistance.
We connect the probes to the sensor and lower the DTOZH into water so that its contacts do not get wet.

We compare the obtained readings with the table below.

If the parameters do not match, then the sensor is faulty and requires replacement.

How to remove and install?

Which is connected to the computer, installed on the outlet pipe of the cooling jacket of the cylinder head of the VAZ 2114. The temperature indicator is nearby, but so that it is convenient from twist, you need to remove the air filter.

So, the sequence of actions:

1. Remove the wire from the minus terminal of the battery.

2. Drain everything from the radiator - not necessarily from the entire cooling system, from the radiator is enough.

3. Disconnect the wiring from the faulty part.

Replacement

Replacing the sensor is not difficult, but you need to prepare a tool. There are two replacement methods: with complete draining of antifreeze and without draining antifreeze. Since the first method is more expensive and time-consuming, we will consider the second without draining the coolant.

Let's get started

Attention!: Work must be carried out on a cool engine to avoid burns!

We unscrew the cap of the expansion tank to relieve pressure in the SOD and screw it back on.

We remove the air filter housing by unscrewing the clamp securing the corrugation to the mass air flow sensor, remove the mass air flow sensor chip and unscrew the housing from the car body.

Remove the connector from the sensor.

Place a cloth under the thermostat to avoid spilling liquid on the internal combustion engine.

We prepare a new sensor by placing it on the battery.

Using an open-end wrench, unscrew the sensor and sharply remove it, plugging the hole in the thermostat with your finger.

We take a new sensor and install it as quickly as possible so that the liquid does not spill.

Install the removed parts in reverse order.

We start the internal combustion engine and check the coolant level, if necessary add antifreeze to the MAX mark.

Why does the VAZ-2114 not show the engine temperature?

Video about diagnosing the temperature gauge (problem overview):

The video will tell you how to check and find the reason for the temperature gauge needle hanging up.

DTOZH on VAZ 2114: we study the signs of malfunction, check and replace the sensor

DTOZH is one of the fourteenth sensors, the correct functioning of which directly affects the ability of the vehicle to operate normally.

From this article you will learn why the coolant temperature sensor is so important, what malfunctions can occur during its operation and what signs can be used to identify a failed device; the technology for dismantling and installing a new sensor on a VAZ 2114 will also be discussed in detail.

DTOZH for VAZ 2114

Causes of malfunction

Arrow stuck on dashboard

It’s probably no secret to anyone that the arrows hanging on the dashboard are inextricably linked with the electrical circuits in the car. To troubleshoot the problem, the car enthusiast will need some knowledge of auto electrics, as well as design knowledge of the VAZ-2114.

As practice shows, most motorists, when such a breakdown occurs, turn to a car service center, but this problem can be eliminated on their own. But, first of all, it is necessary to find the immediate cause of the effect.

What are the options?

So, let's look at the possible options for the engine temperature indicator arrow to hang on the dashboard:

The magnetic motor of the pointer drive is broken.
Breaks and disturbances in the operation of the electrical circuits of the dashboard.
Short circuit in the circuit board of the device itself.
Freeze related to temperature sensor.
Problems with the ECU.

Elimination methods

Once the root causes have been identified, you can move directly to methods to resolve the problem.

To carry out repair and diagnostic operations, you will need some tools, namely: a multimeter, an OBD II cable, a tablet or laptop, as well as a set of keys and screwdrivers for dismantling the main and auxiliary components.

So, now that the motorist is fully armed, you can proceed directly to the diagnostic and repair process.

OPERATING PRINCIPLE AND DESIGN FEATURES

The VAZ 2114 coolant temperature sensor, for all its importance for the normal operation of the car, is a fairly simple device. DTOZH is a resistor with variable resistance, which changes as the temperature of the antifreeze in the system increases.

The sensor has only two contacts - the first of them transmits information about the current coolant temperature to the brains of the fourteenth, and the second sends a signal to turn on the fan (when the coolant temperature reaches a certain point).

Based on the received readings, the fourteenth ECU determines the composition of the fuel mixture supplied to the combustion chambers: the colder the engine, the richer the mixture. The coolant temperature affects how almost all engine control systems will operate: this data is taken into account when adjusting the ignition angle (the moment the spark is supplied for fuel combustion in the cylinders), the time the fan is turned on for forced cooling of the power unit, and much more.

The DTOZH is a fairly durable design; it rarely breaks down, but if the unit breaks down, its repair is impossible - the device must be replaced with a new one. The cost of DTOZh varies between 400-550 rubles. for domestically produced models (the VAZ 2115 coolant temperature sensor costs about the same).

How to check the device for serviceability

So, you have noticed that your motor often gets very hot, or you have discovered other negative signs associated with the cooling device. To begin with, you should check this device, and there are two ways, which we will take a closer look at.

The first option is to remove the device

With the engine running, check the readings shown on the instruments. If the arrow is at the maximum height, then the engine is still in a cold state. Here you should break the contacts on the device and look: if the arrow points down, then it’s time to replace the coolant temperature sensor of your car.
When the pointer remains in the same place, try to examine the system contacts; a short circuit often occurs in them. Then the problem can be fixed much faster.
Another type of failure: the engine heats up evenly, and the instrument needle begins to jump in one direction or another. There is a high probability that the issue is with fuses that are inoperative.
If the fuses are working, it is necessary to close the contact to ground, and again, if the arrow sharply goes up, you can safely state that there is a malfunction in the operation of the DTOZH.

Second option

You need to take a multimeter and turn it on in resistance mode.
Then arm yourself with a thermometer that has notches above one hundred degrees Celsius.
Take a durable container that will not deform when the coolant is heated to a high temperature.
After that, you need to connect the probes of the device to the sensor.
Having made the necessary connections, the DTOZH is placed in a prepared heat-resistant container and heated.
Here you should monitor the performance of two devices at once.

Below is the data by which you can determine the health of the sensor. The method allows you to check a new device before installing it in place of a faulty device.

The first indicators are temperature C, the second indicate resistance in Ohms.

30 – 1350-1880
50 – 585-820
70 – 280-390
90 — 155-196
110 — 87-109

conclusions

There are not many reasons why the VAZ-2114 engine temperature needle goes off scale, but all of them are quite difficult to diagnose, and some can only be eliminated in a car service center. Therefore, if the motorist has not carried out repair operations of this nature, it is necessary to contact a car service center, where they will help and repair everything.

Sources used:

https://carfrance.ru/vaz-2114-ne-pokazyvaet-temperaturu-dvigatelya/
https://vaz-2114.info/priznaki-neispravnosti-dtozh-na-vaz-2114/
https://autovaz-2114.ru/electrical-equipment-in-the-car/dtozh-na-vaz-2114-izuchaem-priznaki-neispravnosti-proveryaem-i-zamenyaem-datchik/
https://carfrance.ru/vaz-2114-strelka-temperatury-dvigatelya-zashkalivaet/