Coolant temperature sensor connection diagram

Actually, it stands but doesn’t really show anything. The indicator from VAZ is installed, but the temperature sensor is from Renault Rapid. The resistance of the pointer and the sensor are different - as a result, the pointer, roughly speaking, shows the average temperature on the moon. The VAZ sensor doesn’t seem to fit (purely visually the diameter is larger + thread for a cone).

Now, actually, the question for knowledgeable people is which sensor to install instead of the standard one so that the indicator readings are correct.

Well, some photos and a wiring diagram for all this. Perhaps it will be useful.

The white wire and the white and black wire go to the indicator light bulb (I connected it like this - white and black - to ground, and the white wire - to the dimensions on the dragonfly. It turns out that the light is turned on - the indicator lights up)

Green - to the temperature sensor, which is located on the engine (located on the left side behind the pump closer to the cabin)

Orange to any positive from the ignition switch (do not throw directly on the battery, otherwise it will work constantly, regardless of whether the ignition is on). You shouldn’t connect it to the white wire either - as soon as you turn on the dimensions, it will lie (mine constantly showed a temperature of 120 degrees)

I also installed the original expansion tank, instead of the VAZ garbage.

The coolant temperature sensor (CTS) is an important element of the engine management system that monitors the coolant temperature in the cooling system. The engine control unit receives information from the DTOZH and, in accordance with it, adjusts the composition of the fuel-air mixture, crankshaft speed, and ignition timing.

Design and principle of operation of the coolant temperature sensor

The “progenitor” of the modern coolant temperature sensor was a thermal relay

, which was installed on some engines (for example, in the K-Jetronic distributed injection system). The thermal relay contact is open - the engine is warming up, the contact is closed - the engine is operating at its normal temperature.

Currently, the basis of the coolant temperature sensor is a thermistor

(a resistor that measures resistance depending on temperature). The coolant temperature is monitored continuously. The material used to make a thermistor is usually nickel or cobalt oxide. The peculiarity of these compounds is that as the temperature increases, the number of free electrons increases and, accordingly, the resistance decreases.

Most often, the thermistor, which is located inside the DTOZH, has a negative temperature coefficient

. The sensor has maximum resistance when the engine is cold. A voltage (5V) is applied to the coolant temperature sensor, and as the resistance changes, it decreases. The engine control unit records voltage changes and, in accordance with it, determines the coolant temperature.

Methods for checking temperature sensors

If the driver wants to make sure that the cause of problems with the car is the antifreeze sensor, then he will have to carry out a simple checking procedure. But before you start, you need to make sure the integrity of the car wiring. As mentioned above, for the sensor to work normally, it must be continuously supplied with a voltage of 5 volts. To make sure that the supplied voltage does not deviate from this value, you should start the car, and then remove the wires from the sensor and connect them to a multimeter. If the device clearly shows 5 volts, then there are no problems with the wiring and you can begin 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.

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

The thermometer and sensor are placed in a container of water

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

Checking without an 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 sensor resistance will be at one hundred degrees. The sensor is connected to a multimeter switched to resistance measurement mode, and then immersed in boiling water. However, you should not expect the multimeter to show a resistance of 177 ohms, which corresponds to a temperature of one hundred degrees. The fact is that the temperature of water constantly decreases during the boiling process and averages 94–96 °C. Therefore, the resistance on the multimeter will vary from 195 to 210 ohms. And if the numbers produced by the multimeter differ from the above by more than 10%, the sensor is faulty and it’s time to change it.

Where is the coolant temperature sensor located?

The thermistor is located inside a protective heat-conducting housing, and on the housing itself there is a thread for attaching the sensor, as well as an electrical connector. Typically, the DTOZH is screwed into the exhaust pipe of the cylinder head. Some engines have two sensors at once: one records the temperature at the engine outlet, the second - from the radiator.

The coolant temperature sensor is positioned so that its tip has direct contact with the coolant. Accordingly, if there is little antifreeze in the system, then the DTO indicators may be inaccurate.

Oil pressure

On “sixes” and other classic models, a VAZ 2106 oil pressure sensor of type Mm393A is installed. The pressure indicator works on the principle of converting this parameter, which is created in the lubrication system, into resistance. The oil pressure sensor is installed in the engine cylinder block. A regulator is also installed here, which turns on the oil pressure light.

This element is triggered as a result of the closing and opening of contacts at a particular level of pressure in the system. The corresponding indicator on the control panel may light up if the characteristics are violated, namely, if there is little liquid in the system.

Designation of part elements

How to check the controller? You can check the engine fluid pressure sensor by removing the regulator from its installation location. After removal, you should turn the starter; you do not need to start the power unit. If everything is fine with the supply of consumables, then you need to change the regulator. You can tell about the oil supply by the splashing of liquid from the controller seat.

Signs of DTOZH malfunction

Like any other sensor, the DTOZH can fail, causing engine malfunctions. The first signs by which you can recognize a breakdown of the coolant temperature sensor:

• problems starting the engine in cold weather,
• bad exhaust on a cold engine,
• increased fuel consumption, etc.

Most often, if such symptoms occur, replacing the coolant temperature sensor is not necessary.

. Most likely, the problem is a loose or damaged contact, damaged wiring, or a coolant leak. Therefore, first you should conduct a visual inspection of the sensor for damage or corrosion.

VAZ cooling fan connection diagram

All the main electrical circuits and modifications for connecting the liquid cooling fan (CO) in VAZ cars of various models are provided. What is the essence of VO’s work? An electric motor with an impeller on a shaft is installed inside a rectangular metal frame, with which it is attached to the back of the radiator. When voltage (12 V) is applied to the contacts of the drive, it begins to work, rotating the blades and creating a directed stream of air, which, in fact, cools the antifreeze or antifreeze.

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Checking the coolant temperature sensor

If the inspection does not produce results, it is necessary to measure the resistance and voltage of the sensor at different temperatures

. After starting a cold engine, as it warms up, the resistance should drop (or increase in the case of a positive temperature coefficient of the sensor) in accordance with normal values.

You can check the coolant temperature sensor yourself

Normal resistance and voltage readings for a NTC coolant temperature sensor

Normal resistance and voltage indicators for DTOZh with a positive temperature coefficient

AutoOt.ru » Car repair » Where is the coolant temperature sensor located?

How to check the coolant temperature sensor?

In order to check the device, it must first be removed.

Dismantling is very simple:

1. As a rule, the sensor is located on the cylinder head pipe and in order to remove it, you first need to remove the air filter;
2. then the negative cable is removed from the battery;
3. coolant is drained from the radiator;
4. the wiring is disconnected from the device;
5. using a suitable wrench (most often 19–21), the tightening is loosened, after which the sensor can be easily dismantled.

After the sensor has been removed, it is placed in a container with coolant and it is gradually heated. The process is accompanied by constant monitoring of the temperature and the readings of an ohmmeter, which is connected to the sensor.

There is a special table corresponding to the coolant temperature and ohmmeter readings.

When the readings from your device do not agree with the data from the table, the sensor must be replaced, since it can no longer be repaired.

If it turns out that the sensor is in working order, the fault needs to be looked for further. There may be some problem with the thermostat.

You can see an example of how to check the coolant temperature sensor by watching this video:

Like a boat

The service life and frequency of maintenance of ship engines or generator sets are assessed in engine hours, and not in the kilometers familiar to motorists. But why track the engine hours of cars? This makes sense when the mileage is short and the engine works a lot - at low, below 15 km/h, average speed. In other words, this is driving in traffic jams or with prolonged idling (idling). Motor oil ages faster and needs to be changed more often. It is undesirable for the engine to run for more than 300 hours on one oil fill; an hour meter will help with this.

The price of the device is 300–350 rubles in the “counter only” version and 400–450 rubles if the counter is combined with a clock. Installation is extremely simple: we connect the meter to two wires on which voltage appears when the ignition is turned on. The result is shown with an accuracy of one hour by seven-segment indicators. There are other types of hour meters - with mechanical drums, like the odometer in old cars, and with liquid crystal displays. The price of these and other devices in the “marine” version exceeds 1000 rubles.

The hour meter is connected to the “minus” and “plus” after the ignition switch. This quite aesthetic device with an LED indicator begins to give readings immediately after starting the engine.

The temperature meter can be designed for outside air or for the engine.

Signs of DTOZH malfunction

The liquid cooling sensor, like any other sensor, can have malfunctions that will someday lead to engine malfunctions.

The main signs that indicate a device failure:

• increased fuel consumption;
• poor exhaust when the engine is cold;
• Problems starting the engine in cold weather.

As a rule, if such problems occur, replacement of the sensor is not required. The problem may have arisen due to a loose or damaged contact, a wiring problem, or a leak of cooling fluid.

Sometimes a cold engine stalls and stalls, and its idle speed jumps from minimum to maximum values ​​per minute, and after a few minutes or after a restart the situation is corrected.

This problem can occur due to a breakdown of the cooling fluid temperature sensor.

You can check the condition of the device using an ohmmeter. There is no need to unscrew it. It is not its resistance that is checked, but the mass sensor.

When the sensor is in order, the resistance tends to infinity, but if it is broken, then the resistance is 10 kOhm or less.

Purpose of the device

DTOZH should not be confused with an antifreeze level controller. If the first is intended to detect the temperature of the power unit, then the second is used to control the volume of consumables - refrigerant. Based on the DTOZH readings, the control unit detects temperature changes and transmits data to the on-board computer about the state in which the engine is operating. Using the controller, engine warm-up, overheating, and the optimal temperature of the operating internal combustion engine are determined. Pulses transmitted to the control module determine the functionality of the internal combustion engine control system as a whole.

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The engine temperature determines the following nuances:

• fuel consumption per 100 km;
• volume and quality of gases;
• ignition of the air-fuel mixture;
• optimal operation of the gearbox.

All these factors are controlled by a control device, which, based on the information received, determines the optimal operating mode of the engine. Therefore, the performance of the temperature sensor is important for the vehicle. If the device is faulty and sends incorrect pulses to the control module, this can lead to problems.

How does DTOZh affect the operation of the internal combustion engine?

Based on the parameters supplied to the control device, the module performs the following functions:

1. Enrichment of the air-fuel mixture or its depletion. If the controller detects that the temperature is too low, it will begin to increase the duration of the signal sent to the injectors, which helps to enrich the fuel mixture. In accordance with the normalization of the temperature regime, the fuel is gradually depleted, which prevents possible excessive consumption of gasoline and reduces the volume of exhaust gases. If the sensor breaks down, it can regularly lower the temperature in the engine, which will lead to fuel contamination and increased consumption.
2. The control unit sets the ignition. It can be early or late. If the temperature increases, the control module adjusts the ignition timing to reduce exhaust toxicity.
3. Thanks to DTOZH, proper recirculation of gases is performed during warming up. The recirculation valve closes tightly when the power unit warms up. If the car’s engine is still cold, then recirculation will cause fluctuations in idle speed and random engine stops.
4. With the help of DTOZH, the control unit purges the filtration system, which traps fuel vapors. To achieve better machine controllability, the carbon filter element is not purged until the engine is completely warmed up.
5. Locking of the gearbox torque converter when the internal combustion engine warms up. The control module should not limit the operation of the device until the machine warms up.
6. The ECU controls the operation of the unit's cooling fan. Based on the temperature controller readings, the module activates and deactivates the ventilation device to correctly select the temperature of the unit. If the DTOZ gives incorrect impulses, there is a possibility of the motor overheating.

How to connect the coolant temperature sensor?

The sensor is installed very easily: it is screwed into the mounting socket, after which the thread is tightened and the wiring is connected, the air filter is put in place and the main air flow sensor power supply block is connected.

It is strictly forbidden to use sealant in this case. When the engine is running, the cooling system and metal elements become very hot, and the sealant may melt.

If this happens, the sealant will get into the antifreeze and the cooling system may fail.

Coolant temperature sensor connection diagram:

Replacing DTOZH, video:

Types of sensors

The coolant temperature sensor can be of two types:

• Mechanical;
• Digital.

A mechanical sensor is the simplest device that transmits parameters of changes in electrical resistance due to electrical signals. This sensor is connected to the temperature indicator on the car's dashboard, and this indicator is usually an odometer with an arrow and divisions in degrees. A relay works in conjunction with this unit, which, when closed, turns on the fans. Mechanical sensors are found on almost all carburetor cars.

A digital sensor is very similar in appearance and design to a mechanical one, only it sends signals not directly to the fan and dashboard, but to the electronic control unit. The ECU is equipped with a processor that, analyzing all incoming signals, issues commands to the cooling and ignition systems, and also displays temperature readings on the instrument panel.

There are also sensors:

• Magnetic;
• Bimetallic;
• Capillary (not used in modern cars).

Checking the coolant level

Many car owners often check the coolant level visually without using special instruments. You just need to look at the expansion tank.

If the engine is cold, the coolant should be between the maximum and minimum marks on the reservoir. When the engine is warm, the level of the substance may increase slightly.

If your car is in full working order, then when the antifreeze level decreases, the sensor immediately lets you know about it. The driver sees a special signal on the dashboard and adds antifreeze or coolant.

It is also contraindicated to add water alone. After all, antifreeze has special properties that protect cylinder heads from corrosion.

If checking the coolant temperature sensor does not show the coolant temperature. In this case, you better contact technical service.

In any car, everything is interconnected. The car system could fail for some related reason. For example, you could remove some part located with the sensor and place it incorrectly.

But it also happens that the problem is related specifically to the temperature sensor. The coolant level may be inconsistent or there may be a problem with the coolant level sensor.

The service can replace the sensor, and they provide a guarantee for its high-quality replacement and the correct assembly of all parts in the right places.

Thus, the coolant temperature sensor is a very important component of your car, which requires constant attention and care.

If repair of this device is necessary, then do it efficiently, without regretting the money spent. After repair, the engine will run smoothly, this will be especially noticeable at low speeds.

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Replacement

Replacing a faulty DVT is very simple.

Step-by-step instruction:

1. Wait until the engine has completely cooled down.
2. If necessary, drain the antifreeze from the system.
3. Disconnect the negative terminal on the battery.
4. Disconnect the plug terminal from the sensor.
5. Unscrew the element.

Replacement is carried out in the reverse order. After completing the procedure, you need to turn on the ignition without starting the engine. The ECU must read the new part and conduct internal diagnostics. If the cause of the problem cannot be clarified, it is better to contact a specialized service.

The coolant sensor is a very important part of the car. Therefore, for replacement it is necessary to purchase only original spare parts. You can determine the original production of DTOZH by the article number indicated on the packaging. Sensors for domestic VAZ cars are marked with article number 2101-3808600. The originality of models from foreign manufacturers for VAZ cars and foreign cars can be determined from the table below.

You should not install similar components from cars of other models. The electronic circuit may be different, the sensor will produce premature, late, inaccurate data, which will affect the overall performance of the vehicle. Each sensor is assembled taking into account engine volume, its power, and the total volume of coolant in the system.

The cooling system is an important part of car systems. A faulty sensor can affect both the operation of the engine and the integrity of its components. This part is quite cheap in terms of cost. Replacing it will help avoid a number of engine problems, as well as large financial investments.