Favorite symptoms and solutions sensor ⚙️ tuby.men

1. What is the temperature sensor of an engine?

The engine of a car is a complex system, visited by many indicators. One of these is the temperature sensor that monitors the temperature and prevents the engine overheating. The temperature sensor consists of two electrical conductive contacts and a cone -shaped work element, made with a sensitive material. The change of the degree of electric conductivity is recorded and, therefore, the sensor provides information on the temperature and reaching its critical thresholds.

Convenient, two types of temperature sensors can be distinguished, that is to say:

• Mechanically: information on the resistance of the material is made «analog» through an electrical signal.
• Digital: since a design does not differ too much from the mechanical one, but the temperature information is transmitted through the bus, directly to the ECU digital control unit.

2. How does the temperature sensor work?

The functioning of the temperature sensor is performed on the basis of the physical properties of the sensor material, in order to change its electrical resistance depending on the degree of heating.

The temperature sensor is a device that controls the heating of the cooling liquid. When it reaches the maximum (criticism) temperature, sends a signal to the ECU unit, which in turn starts the radiator fan. In this way the excess temperature is restored, which prevents the overheating of the engine, bringing it to the normal operational phase.

This sensor that sends information on the «heating» indirectly participates in the formation of the fuel mixture, because a cold engine needs more fuel than a hot one.

3. Where is the temperature sensor?

The cooling sensor is always in the liquid to provide correct information. If it is not immersed in a liquid environment, it means that it will not work correctly! The producers understood it and, therefore, install them only in those places that will always be (also with depressurization), «near» the cooling liquid. Usually this is the housing of the thermostat, in the cylinder block, rarely in the head of the block. For safety reasons, it is recommended that on some foreign cars in the premium segment there are 2 sensors simultaneously, fixed in different places: one on the thermostat, the other on the engine block. They perform different tasks, for example, information is transmitted on the temperature of the liquid to the ECU unit and the car panel, the other can control the initial function of the cooling fan.

4. What role does the temperature sensor play?

The entire group of the motor temperature sensor generates high temperatures, with very high speed. The process through which the combustion of fuel and oxygen is performed is repeated several thousand times per minute, producing temperatures above 2000 ° C. Therefore, it is obvious that the engine (diesel or petrol) works with a cooling liquid, to which the heat from the metal parts is quickly transferred. The cooling liquid penetrates the engine block through a pipe system, then reaches the radiator, where the heat collected through the circuit is evacuated. During this course, the temperature sensor has the role of monitoring the liquid temperature and transmits to the injection computer. The precise measurement of the temperature maintains the engine speed at a constant level, through an optimal mixture of aerial power supply in the combustion chamber. The element that allows the sensor to detect temperature variations in the engine is called thermistor and is a device whose electrical resistance decreases with the increase in the heat level. Each manufacturer prescribes an optimal value of the resistance of the sensor thermistors of each engine model.

Another role of the temperature sensor is to avoid the imbalance in the combustion process of the fuel mixture, which influences the level of polluting emissions, detected in ITP.

5. What symptoms does the car have if the temperature sensor is defective?

Very often, these temperature sensors are monobloc, therefore, in case of bankruptcy, they are replaced with new others. This applies to all types of cars. Checking a sensor is a simple operation. In 90% of cases, there are only a few defects that can be visually identified, as follows:

• The terminal unit of the sensor can oxidize from time to time: the sensor is removed and clean
• There is corrosion. Sometimes contacts rot.
• Create in the housing and traces of drainage. The sensor must be changed.

These are just some operations that anyone can do, but there are others that require the intervention of the specialist, when it is necessary to resort to an authorized service. Here are some of these:

• An error on the dashboard indicating the cooling sensor
• Difficulty in starting the engine even hot; The hot engine stops at the ranks, followed by a difficult start.
• Fuel consumption increases a lot.
• Co’s errors appear or catalyze errors on the dashboard.
• The constant overheating of the engine, with a normal volume of liquid and with the correct functioning of the cooling fan.

All this information converge towards a sensor defect.

6. Diagnosis of the temperature measurement circuit

In order to diagnose the temperature measurement circuit when the error code P0180 are required, a digital voltmeter/digital ohmeter, oscilloscope, infrared thermometer and vehicle information. The first diagnosis of the temperature measurement circuit begins with a visual inspection of all the wiring and associated connectors, after which the elements used are replaced.

The fuel temperature sensor (incorporated into the fuel composition sensor), is supplied with a 5 Volt reference and divided. Use DVOM to check the reference voltage and grounding of the fuel temperature sensor connector. If there is no voltage reference, use DVOM to test the circuits corresponding to the PCM connector. Rimed the circuits if there is a voltage reference signal to the PCM connector. If there is no tension to PCM, it is suspected that this is defective or a programming error. PCM’s replacement or reprogramming will need a specialist. If the temperature indicated by the thermometer does not correspond to that displayed by the temperature sensor, the temperature sensor is defective.

Additional diagnosis Note:

• Use DVOM to test the resistance of the fuel temperature sensor according to the manufacturer’s recommendations.
• It detects all relevant controllers before testing the resistance of the circuit with DVOM.

7. OBD defect codes of the temperature measurement circuit

P0180 – Fuel temperature sensor Circuit

This code of error diagnosis (DTC) is a generic transmission code that appears in vehicles equipped with OBD-II (Nissan, Ford, Fiat, Chevrolet, Mercedes, Dodge … etc.).

If the error code P0180 appeared in your car, it simply means that control of the control group (PCM) has detected a voltage signal from the fuel temperature sensor. The temperature sensor is located in a single housing (together with the flexible fuel sensor, known as the fuel composition sensor). The fuel that passes through the sensor under construction -in is monitored to determine its degree of contamination. This sensor sends an electrical signal to the PCM that reflects, not only which pollutants are present, but also the degree of contamination. The degree of fuel pollution is taken from the PCM in the form of a rectangular wave of tension. The shape of the waves changes its frequency depending on the degree of fuel contamination. The horizontal position of the wave form, or the width of the impulse, indicates the fuel temperature. The greater the width, the greater the fuel temperature. The P0180 will also store the flashing light indicator (MIL).

Depending on Engine architectureThe measurement circuit of its temperature can also contain the second sensor, which has the following OBD2 codes.

8. What dysfunctions can be caused by a sensor failure

The defect of the temperature sensor can lead to the destruction of the engine. The information transmitted by a problematic temperature sensor to the ECU unit is not correct, consequently, the supply of fuel and the ignition of the fuel are made erroneously. A overheated engine can stop ignition or stop walking. In addition, the engine can overheat, reach the boiling phase, but the data transmitted to the Auk are not correct. In conclusion, the engine can be traveled.

9. How do you act when you have problems with the temperature sensor

It is worth noting that the temperature sensor is quite rare, if the car is well maintained, more often they transmit incorrect information to the Auk. The temperature sensor is a rather simple device and which controls its functionality does not require special knowledge and experiences. For verification it is sufficient to have a tool for disassembly (a key) and a multimeter. Therefore, the simplest thing is to compare the two temperatures on the dashboard with that obtained from the cooling liquid temperature sensor, according to the next table. If these data differ, it is logical to remove that sensor and if you don’t understand, you go to a service to make a further and replace.

Read the sensors compared to the change of temperature

It is worth noting that a cold engine will have a driver’s resistance (Ohm), while a hot engine will have much lower resistance of the driver.