03/09/2020 3,627 Sensors
Author: Victor
The cooling system plays an important role in the operation of the engine - its purpose is to cool the components of the power unit, which become very hot during its operation. One of the main elements of this system is the coolant temperature sensor. You can learn more about its purpose, operating principle and replacement from this article.
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Characteristics of the coolant temperature sensor
So, what is the main or additional coolant temperature sensor (DTOZH), what is its device, what functions does the element installed in the cooling system perform? First, we suggest finding out where the engine temperature sensor is located and what functions it performs.
Purpose and location
The TOZ sensor is a device used to support the optimal operation of the main components of the vehicle. This regulator allows you to quickly warm up the engine and also prevent it from overheating. The TOZh sensor is small in size, however, its importance cannot be denied. If the coolant sensor is faulty for some reason, this can lead to more serious consequences. Especially if the malfunction of the coolant temperature sensor is detected untimely.
Installation location of the regulator in Lada
The regulator itself is a fairly small device, made in a plastic case and equipped with a steel thread. If you are wondering where the coolant temperature sensor is located, we will now give you the answer. Using a thread, the device can be installed and connected to the outlet line of the BC head by simply screwing into it.
Depending on the design features of the car, it can also stand next to the thermostat housing or directly on the body. The car temperature sensor must be positioned in such a way that it is in direct contact with the consumable. Accordingly, if the level of antifreeze in the system is too low, the sensor readings may be incorrect.
Some car enthusiasts confuse the concepts; for them, DTOZH is the same as a coolant level sensor or a temperature and air pressure sensor. This is fundamentally wrong, since the coolant level sensor is used to determine the volume of consumables. Its role is not as significant as that of the DTOZH. Moreover, the coolant level sensor is located in the coolant expansion tank. Depending on the design features of the car, two DTOZH can be used - one of them determines the temperature at the outlet of the engine, and the other - from the radiator.
Design and principle of operation
How does the coolant temperature sensor work? We’ve sorted out the location and purpose, now let’s look at the design and principle of operation. The main structural component is a resistor thermistor, which changes the resistance of the coolant temperature sensor in accordance with the temperature conditions. This component is installed in a threaded steel housing, to which is connected a plastic tail section, where the contacts used to connect the wiring are located. The connection diagram for the coolant temperature sensor is quite simple. One contact of the regulator is a plus, it connects to the ECU, and the second is a minus, it connects to ground (the author of the video is the channel Valerii1986).
For the device to work properly, it needs 5 volts of power, which is supplied from the ECU using a resistor with a constant resistance. Since the thermistor itself has a negative coefficient, its resistance level will decrease as the temperature increases. Accordingly, the voltage level that powers the regulator will drop. In accordance with the drop in this parameter, the ECU calculates the temperature of the engine, and the readings are displayed on the dashboard. A high signal level of the coolant temperature sensor, which the driver can find out from the controller with a signal arrow on the dashboard, may indicate a malfunction.
Displaying temperature data on the instrument panel
AvtoVAZ manufacturers answered the question of experienced mechanics: why there are no heating degrees on the instrument panels of vehicles from the Russian manufacturer. They claim that this was done because it was unnecessary to display these numbers. Because the engine is configured in such a way that the temperature in it is always maintained at an optimal temperature. There were no cases of overheating.
Attention! AvtoVAZ manufacturers allow car owners not to warm up the car. They refer to European environmental standards. Allegedly, by not warming up the engine, the car owner does not destroy nature and saves fuel.
However, experienced mechanics and car owners managed to display information on the dashboard screen. Some even buy special devices to determine engine temperature.
Now we’ll find out how to check the engine temperature on a Lada Granta car.
On ordinary Russian-made cars, although there is no engine temperature scale, in top trim levels, or as they are also called “Lux”, this scale remains. It is called the coolant or antifreeze temperature scale.
On other machines, only places for installing additional devices for determining this data are provided. Now, you need to find out whether the ECU firmware will show the temperature if the car owner installs additional devices.
The procedure is:
- Turn off the ignition.
- Press the daily mileage reset button and turn the ignition key to the “Start” position.
- Now notice that all the indicators turn on and the arrows on the panel move. This means that the system has entered service mode.
- You need to release the reset key.
- Press it again.
- The numbers that appear on the scale indicate the firmware version.
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? Let's see if it is possible to flash the equipment so that it shows the engine temperature.
For Grant Standard:
- 015 – not possible due to the old modification of the motherboard;
- 029 – 040 – not possible due to the old modification of the board;
- 053, 060, 076, 087 - you will have to work with a soldering tool. Experienced mechanics reflash the device to the new 2190-20 092 For 076.
For Grant Norm:
- 090, 091 – it is allowed to change the air heating sensor on the street, you cannot install DTOZH;
- 092-095 – it is allowed to change the air heating sensor, you can also change the TOZh sensor;
- 032, 038, 042 – it is possible to change the outside air heating sensor, you cannot install DTOZH.
For Grant Lux:
- 046 – allowed;
- 047 – allowed;
- 007 – it is allowed to replace the system with 046.
For Kalina Norma:
- 014 – possible;
- 009 – you can.
For Kalina Lux:
- 012 – possible;
- 014 – it’s possible.
Now you will need to flash the ECU with a new program. They do this as follows:
- Pull out the panel and connect the programmer device to it.
- Upload new firmware.
- Turn on the ignition and poke the buttons with your finger, watching how the icons switch on the screen.
- Switch until the screen displays the motor temperature.
This completes the display of motor heating on the toolbar screen.
Symptoms of a controller malfunction
Now let's look at the signs of a malfunctioning coolant temperature sensor. Overall, this controller is quite reliable because its design is simple. However, malfunctions may occur during the operation of this device. As a rule, they are caused by a violation of calibration, which, in turn, affects the incorrect operation of the ECU, since this unit performs some of the options taking into account the temperature conditions of the motor. If the temperature gauge does not work, then the primary sign of its failure is the failure of the fan to turn on.
However, this symptom is not fundamental; more precisely, I can say the following symptoms about the failure of the regulator:
- increased fuel consumption;
- increased engine speed when idling;
- if the sensor does not work, this can also lead to detonation in the engine;
- there is a possibility that the engine will be difficult to start when hot;
- engine overheating (video author: Denis Tsirkunov).
You need to be most careful with the last symptom, since this symptom can lead to damage to the block head. In older cars, the controller on the dashboard allows you to determine the malfunction - if you see that the device’s arrow has moved beyond the standard mark, you need to stop the car and identify the cause of the problem. In more modern cars, a corresponding message may appear on the on-board computer screen if the engine overheats or the DTO fails. As practice shows, replacing the coolant temperature sensor is usually done in case of oxidation or damage to its contacts; the reason may also be a broken wiring.
Old dashboard
On vehicle models before 2014, it will not be possible to view the temperature on the dashboard in any case. And, if you pay attention only to the overheating light, then when it lights up, it may be too late to save the engine.
In this case, installing a special engine temperature indicator will help. However, you first need to understand what the on-board computer values on the panel mean in order to understand the problem.
On-board computer values on the panel
The manufacturer says that you can drive with an engine that is not warmed up. Although this is fraught with major overhauls not only for the engine, but also for the automatic transmission. If you warm up the engine, then in hot regions you may not understand when the engine warms up to 80 degrees, and the temperature jumps above the set point. And when the engine starts to boil, it will be too late to wave your hands.
So how do you know that the heating levels in the engine have reached their climax? In this case, experienced mechanics suggest installing a special engine temperature indicator.
Installing a separate engine temperature indicator
A similar engine temperature indicator is installed in any free hole in the car interior. The installation procedure itself does not take much time.
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Attention! First you need to turn off all power in the car. It is best to remove the terminals from the battery.
Now you can begin the procedure:
- Remove the panel trim.
- Since the battery mass has already been disconnected, we proceed to the procedure for opening the glove compartment lid.
- Find the diagnostic connector and pull it out.
- Then a temperature indicator is placed in place of the plug and the wires are connected.
- The other end of the wires is connected to the diagnostic connector and clamped.
Now you can turn on the power to the car using the battery and start the car. The engine temperature indicator should turn on and indicate a combination of numbers indicating degrees Celsius.
View the temperature using a smartphone or tablet
On modern Lada Granta or Kalina, you can view the temperature using a smartphone or tablet. Only to perform this procedure, the car owner will need to buy a special cable.
This cable works via Bluetooth. You will also need to download a special program to your phone with the Android operating system. Using it, it will be possible to view the engine heating degrees.
The connection process is as follows:
- Turn off power.
- Pull out the diagnostic connector.
- Insert the diagnostic cable into it and secure it.
- The program you need to download is called “Torque”.
- Now you should start the engine and turn on the utility on your phone.
- A message will appear on the monitor informing you of the current engine temperature.
Now you know how to view how many degrees on your engine on old Lada Granta panels produced before 2014. Let's see what can be done with the new Lada Granta or Kalina.
Self-diagnosis methods
How to check the coolant temperature sensor? Before removing and replacing the sensor, you need to make sure that it is the problem that is causing the problem. Checking the coolant temperature sensor can be done at home; there are several ways to do this.
First, let's describe the first method - how to check a temperature sensor by placing it in water:
- First, you need to place the thermometer in a container of cold water. Alternatively, you can use a kettle. It is advisable to use an electronic device, since you will need to measure the temperature at elevated temperatures.
- Then you need to connect a tester to the controller - a multimeter, which needs to be set to resistance measurement mode.
- Then the DTOZH itself is installed in the kettle.
- Take readings from the regulator and write them down on a piece of paper.
- Next, the container is placed on the stove and heated, while you must take the resistance values of the DTOZH when reaching the main heating points - 15, 15, 20, 25 degrees, etc.
- After this, it is necessary to compare the obtained values with those given in the table.
Photo gallery “DIY diagnostics”
1. Regulator resistance measurement
2. Table of dependence of DTOZH parameters
If the readings differ from the most optimal, this indicates a breakdown of the regulator, and accordingly, it will need to be changed. There is another diagnostic option. How to check the coolant temperature gauge without a thermometer?
The principle of this method is that when heated, the temperature of the water will be a maximum of 100 degrees, no more. Therefore, this point can be taken as the main value and the resistance can be measured. When the water boils, the regulator's resistance level should be about 177 ohms. If we take into account the errors, then this figure can be approximately 190-210 Ohms.
Actions of the car owner in case of sensor failure
If the regulator is not working correctly, then you have several options:
- make sure that the problem is not a broken wiring; if so, then the damaged circuit must be restored;
- check the contacts for oxidation - to do this, the power wire must be disconnected and the contacts cleaned;
- if these actions do not help, then the only solution is replacement.
New instrument panel
On a Lada Granta with a new instrument panel, the temperature indicator should already be built-in. However, not all cars have it. Therefore, many car owners have to reflash the panel.
Since overheating alarms are no longer installed, the temperature should be displayed on the instrument panel when requested by the car owner. If it is not there, then perhaps the manufacturer installed old firmware and therefore the car owner cannot find the engine temperature on the instrument panel screen.
The instrument panel also displays other values of vehicle parts. For example, gasoline consumption, amount of gasoline, errors in operation of the automatic transmission or engine.
Instructions for removing, replacing and connecting DTOZH
Dismantling the TOZh controller
How to change the coolant temperature sensor with your own hands? Before replacing the controller, you need to know exactly where it is located in your car; you can use the service book to clarify.
The replacement process looks like this:
- Open the hood of the car and unscrew the filler cap of the antifreeze reservoir.
- Then you need to place a container under the refrigerant drain hole, and unscrew the hole cover.
- Disconnect the wire that powers the controller.
- The controller itself, depending on the design features of the car, can be fixed with a latch, a clamp, or screwed in with a thread. Dismantle the device.
- Next, the coolant temperature sensor is installed. Before installation, the replaced device can be treated with a sealant, in particular, we are talking about contacting surfaces.
- Refill with antifreeze.
Price issue
The cost of the device is determined by the model of the car in which it will be used, as well as by the manufacturer. JP GROUP regulators cost about 200 rubles, from the manufacturer BERU - around 350 rubles, from the manufacturer Hella - approximately 700 rubles. Prices are average, excluding car model.
