Car temperature sensor Lada Granta

Such a seemingly insignificant detail of a car as a Lada Grant temperature sensor is one of the most important devices in a car. The safe operation of an internal combustion engine (ICE) depends on its serviceability. A timely identification of the cause of a sharp increase in the temperature of the coolant will save the owner of the vehicle from troubles on the road and large unforeseen expenses.

Lada Granda:

Why does the coolant boil

Sometimes you can find a car standing on the side of the road with the hood up, from under which steam comes out in clubs. This is the result of the failure of the Lada Grant temperature sensor. The device gave incorrect information to the electronic control unit (ECU), and the ventilation system could not work in time, which caused the antifreeze to boil.

With a faulty coolant temperature sensor (DTOZH) on the Lada Granta, antifreeze may boil for several reasons:

1. Timing belt loosening.
2. Pump bearing failure.
3. Faulty thermostat.
4. Antifreeze leak.

Loose timing belt

The belt tension may loosen due to running out of life or poor workmanship. The belt begins to slip over the teeth of the pump drive gear. The speed of movement of antifreeze in the radiator drops, and the temperature rises sharply. The belt is tightened or replaced with a new product.

Timing belt:

Pump bearing failure

The consequence of the failure of the bearings of the water (cooling) pump is that the pump begins to wedge. The antifreeze stops moving inside the large circuit of Grant's cooling system, and the liquid, quickly heating up, reaches a boiling point of 100 ° C. The pump is urgently dismantled and replaced with a new pump.

Pump:

Failure of the thermostat

Over time, the device may exhaust its resource, and when the antifreeze warms up, the valve stops working. As a result, antifreeze cannot circulate through the large circuit and pass through the radiator. The liquid remaining in the engine jacket quickly heats up and boils. The thermostat needs to be replaced urgently.

Thermostat:

Antifreeze leak

This can happen due to leaks in the connections of the pipes of the cooling system, damage to the radiator, expansion tank and pump. A low level of antifreeze can be seen from the markings on the expansion tank. It will also be noticeable by how fast the needle moves or the temperature values ​​​​change on the instrument panel interface. You need to add fluid to the desired level and go to the garage or service station.

Expansion tank:

appointment

The process of ignition of the fuel mixture in the cylinders of the internal combustion engine is accompanied by an increase in temperature up to 20000C. If you do not maintain operating temperature, the cylinder block with all the details will simply collapse. The purpose of the engine cooling system is precisely to maintain the thermal regime of the engine at a safe level.

Grant's engine temperature sensor is the sensor that tells the ECU how hot the coolant is. The electronic unit, in turn, analyzing data from all sensors, including DTOZH, brings all internal combustion engine systems to an optimal and balanced mode of operation.

DTOZH:

The device and the principle of operation

The Grant temperature sensor is a variable resistance thermistor. The thermocouple, enclosed in a bronze case with a threaded tip, reduces the resistance of the electrical circuit when heated. This allows the ECU to determine the coolant temperature.

MOT device:

If we consider the sensor in section, we can see two contact petals located at the top and bottom of the thermistor, made of a special metal alloy, which changes its resistance depending on the degree of heating. Close both contacts. One receives power from the on-board network. The current, having passed through the resistor with a changed characteristic, exits through the second contact and enters the computer microprocessor through the wire.

The following parameters of an internal combustion engine depend on DTOZH:

• temperature sensor readings on the instrument panel;
• timely start of the forced cooling fan of the internal combustion engine;
• fuel mixture enrichment;
• engine idle speed.

Symptoms of a malfunction

All emerging negative phenomena, as soon as DTOZH fails, can be described as follows:

• fuel consumption is greatly increased;
• difficult "cold" start of the engine ";
• when starting, the muffler "breathes";
• the radiator fan runs constantly;
• the fan does not turn on at a critical level of coolant temperature.

Before taking on the disassembly of the meter, experts recommend that you first check the reliability of the wiring and the fastening of the connectors.

Where is

Finding a temperature sensor is not at all difficult. The developers of the VAZ-1290 Lada Granta 91 built the sensor into the thermostat housing. This is just the place in the cooling system where you can set the maximum degree of antifreeze heating. If you lift the hood, you can almost immediately see where the thermostat is located. It is located on the right side of the cylinder head. We find the sensor in the seat of the thermal valve body.

Location of DTOZH (yellow nut visible):

Health check

To check the driver's performance, you need to remove it (how to do this, see below) and prepare the following:

• clean the sensor from dust and dirt;
• digital multimeter;
• thermocouple with sensor or thermometer;
• open container for boiling water.

Multimeter:

Verification Procedure

Checking DTOZH is carried out as follows.

1. Place the dishes with water on the stove and turn on the gas burner or electric stove.
2. The multimeter is set to voltmeter mode. The probe closes the contact with "0" of the counter. The second sensor is connected to another sensor output.
3. The controller is lowered into the bowl so that only its tip remains in the water.
4. In the process of heating water, temperature changes and sensor resistance values ​​are recorded.

The obtained data are compared with the indicators of the following table:

Water temperature in the tank, °C	Sensor resistance, kOhm
0	9.4
10	5.7
twenty	3,5
thirty	2.2
35	1,8
40	1,5
fifty	0,97
60	0,67
70	0,47
80	0,33
90	0,24
one hundred	0,17

If the readings differ from the tabular data, this means that the coolant temperature sensor must be replaced, since such devices cannot be repaired. If the readings are correct, you need to look further for the causes of the malfunction.

Diagnosis by Opendiag mobile

The old way of checking the counter today can already be considered "grandfather". In order not to waste time on boiling water, or even more so to go to a service station to diagnose the electrical equipment of a Lada Grant car, it is enough to have an Android-based smartphone with the Opendiag mobile program loaded and diagnostics ELM327 Bluetooth 1.5 adapter.

Adapter ELM327 Bluetooth 1.5:

Diagnostics is carried out as follows.

1. The adapter is inserted into the Lada Grant diagnostic connector and the ignition is turned on.
2. Select the Bluetooth mode in the phone settings. The display should show the name of the adapted device - OBDII.
3. Enter the default password - 1234.
4. Exit the Bluetooth menu and enter the Opendiag mobile program.
5. After the "Connect" command, error codes will appear on the screen.
6. If errors RO 116-118 are visible on the screen, then the DTOZH itself is faulty.

The interface of the Opendiag mobile program on Android:

Replacement

If you have the skills to handle the simplest tools, replacing a damaged device with a new sensor is not difficult. Before starting work, you must make sure that the engine is cold, the car is standing on a flat area on the handbrake and with the negative terminal removed from the battery. After that, proceed as follows:

1. A contact chip with a wire is removed from the head of the DTOZH connector.
2. Drain some (about ½ liter) of the coolant into a suitable container by removing the bolt at the bottom of the cylinder block.
3. An open-end wrench on "19" unscrews the old sensor.
4. Install a new sensor and insert the contact chip into the DTOZH connector.
5. Antifreeze is added to the expansion tank to the desired level.
6. The terminal is returned to its place in the battery.

With some skill, it is not necessary to drain the coolant. If you quickly squeeze the hole with your finger, and then just as quickly insert and turn the new driver 1-2 turns, then the loss of antifreeze will be a few drops. This will save you from the "cumbersome" operation of draining and then adding antifreeze.

The guarantee against problems in the future will be caution when choosing a new coolant temperature sensor. You should buy devices only from trusted branded manufacturers. If the car is more than 2 years old or the mileage is already 20 thousand km, then a spare DTOZH in the trunk of the Lada Grant will not be superfluous.