Coolant temperature sensor, "Priora": features, device and reviews

2024 Author: Erin Ralphs | [email protected]. Last modified: 2024-02-19 11:42

In Russia, the car "Lada Priora" is very fond of. It is a reliable, simple and affordable car. It uses a modern injection unit from AvtoVAZ as an engine. For the operation of such an internal combustion engine, the serviceability of the coolant temperature sensor is important. "Priora" rarely fails due to a breakdown of this element. But if this happens, motorists need to know what to do.

The principle of operation and the device DTOZH

Earlier, engineers used a primitive thermal switch as temperature sensors. It was installed even on engines with a mono-injector power system. When the contact of this relay is open, the engine warms up. When the contact closes, the ECU thinks the engine is warm.

DTOZH Vase is athermistor. This is a thermistor, the resistance of which depends on the temperature of the antifreeze. Normally, the temperature of the coolant in the engine is continuously monitored. Therefore, thermistors are made of nickel oxide or cob alt oxide (other metals are not used in the design). The peculiarity of these alloys is that with increasing heating, the number of electrons also increases (which means that the resistance decreases).

The thermistor inside the sensor has a negative coefficient. Its resistance is maximum when the motor is cold. The DTOZH is powered by 5 V (permissible error is 0.2 V). As the voltage warms up and the resistance changes, the voltage drops. The ECU monitors voltage changes and, based on these data, determines the temperature of the power unit.

Sensors on other cars (for example, on models from Renault) differ in a positive temperature coefficient. The element is designed in such a way that as the temperature rises, the resistance of the sensor does not fall, but grows.

Features of DTOZH "Priors"

Most owners of these car models often confuse the coolant temperature sensor on the Priore with an element that measures the temperature in the environment and in the cabin. These are two different details. The main task of the first device is the constant monitoring of the temperature indicators of antifreeze in the cooling system.

The Priors uses two sensors. The first is mounted on the cylinder head - it is responsible for displaying information about the temperature of the power unit on the instrument panel. This is the mostordinary pointer. The second element, which is precisely the Priora coolant temperature sensor, performs more important tasks. It transmits electrical impulses to the ECU and then activates the fan. DTOZH plays an important role in the formation of a combustible mixture, as well as in the process of engine operation under load.

Operation principle

DTOZH "Priory" is installed directly in the thermostat housing. This allows for maximum pulse accuracy. Since DTOZH is always in contact with antifreeze, it can almost instantly detect the slightest changes in temperature. It also quickly transmits signals to the ECU. Based on the information received, the car's brain corrects the parameters of the engine by changing the composition of the fuel mixture.

If the antifreeze level is too low, the controller will receive incorrect data, so the engine may run intermittently. The same is observed due to a breakdown of the sensor.

Signs and consequences of malfunctions DTOZH

If the Priors coolant temperature sensor of 16 valves is out of order, then this will immediately entail a lot of trouble. Fuel consumption will increase significantly. Also, due to a richer mixture, the amount of harmful emissions will increase. For the same reason, the engine may not start well “hot”. If the mixture is too rich, there is a risk of piston burnout.

At the same time, the vehicle's dynamic performance and handling will deteriorate. Engineit will take more time to warm up to operating temperature, because due to incorrect signals from the sensor, the computer will turn on the cooling fan. In this case, there is a high risk of overheating.

The sensor is not always completely out of order. All of these symptoms can be caused by oxidized or damaged contacts. Often the cause is wiring or antifreeze leaks. Therefore, you need to remove the sensor and change it only after a thorough inspection of the contacts.

Diagnosis

To check DTOZH in a garage or at home, you need a container of coolant. You also need a thermometer that can accurately measure temperatures up to 120 degrees.

It is necessary to replace the resistance of the sensor in different temperature conditions. Antifreeze during the diagnostic process needs to be heated. The data obtained on the multimeter is compared with the temperature on the thermometer.

So, at 100 degrees, the resistance of the sensor will be approximately 178 ohms. At 90 degrees - 239 ohms, at 82 - 319 ohms. At zero it will be about 7278 ohms.

Where to find DTOZH on the engine

If the sensor is defective, it must be replaced. But not everyone knows where the coolant temperature sensor is located on the Prior. The element that affects the operation of the engine is located inside the thermostat housing. This applies to engines of 1.6 and 1.8 liters with a 16-valve gas distribution mechanism.

Replacement

If the diagnostic procedures showed that the element is in working order, andthe symptoms of a malfunction are still actively manifested, then you need to carefully check the contacts, wiring, connection quality again. If it turns out that the device does not work, the Priora coolant temperature sensor needs to be replaced. Even novice car owners will cope with the replacement process.

There are two Priora engines. Some people think that the replacement procedure will be different on different engines. However, this is not at all the case. Both on the 8 and on the 16-valve engine, everything is done the same way. The thermostat housing is installed in the same place. The only difference is that you need to dismantle the line connecting the air filter to the throttle in advance.

First of all, before replacing, you need to de-energize the on-board network. To do this, you can remove the negative terminal from the battery. Next, a little antifreeze is drained from the radiator. This is necessary so that the coolant does not spill when the DTOZH is unscrewed.

After completing the preparatory procedures, you need to get close to the sensor. If the branch pipe between the throttle and the air filter causes inconvenience, it should be dismantled. To do this, the clamps are disconnected with a screwdriver. Next, the terminal is disconnected from the device, as well as its fastening. After that, they take a suitable head and a collar under it and unscrew the element, after which the part is carefully removed from the seat.

Then, in reverse order, a new DTOZH "Lada Priory" is installed. That he sits securely in his intended place anddid not turn out, it is better to use thread lockers. These funds are sold at any auto shop. After completing these steps, connect the connector, add antifreeze or antifreeze to the system (depending on which coolant was used earlier). As a rule, the liquid is poured to an average level in the tank. Next, check the item for performance. At +40 degrees, the arrow should move.

Conclusion

This is how you can diagnose and replace the Priora coolant temperature sensor. The price of the device is approximately 300-350 rubles. You can buy it at many auto shops. After replacing the sensor, the machine will be back in service. Do not delay this process. Ignoring this problem entails a bunch of unpleasant moments, such as increased fuel consumption and engine operation out of its temperature range.