If there are no speedometer readings on your VAZ 2114, you check the fuses and then accurately diagnose a breakdown of the speed sensor. In this case, unstable idling or sluggish response to the accelerator pedal sends the car owner to diagnose engine sensors. And the reason may not be in them at all. Although the speed sensor on the VAZ 2114 is located in the manual transmission, it may be the culprit of problems that are not related to the gearbox.
This small sensor does more than just count the vehicle's mileage and determine its instantaneous speed.
Its data is used by the electronic engine control unit. The following engine parameters are adjusted using the speedometer sensor:
- idle speed: the ECU compares the crankshaft speed with the actual speed of the car;
- correct formation of the proportion of the fuel-air mixture;
- engine power at the current time;
- fuel consumption, especially when coasting: when the throttle is closed and the speed is fixed, fuel does not flow to the injectors.
Speedometer sensor location
Regardless of the year of manufacture of the car, this device is installed on the gearbox housing .
It is attached to the drive using a threaded connection. To find this sensor you need to look at the gearbox in the area of the right CV joint . Next, you should find a part with a connected electrical connector. Below is a photo of where the VAZ 2114 speedometer sensor is located. On older models, a cable is attached to the device. It is necessary to transmit torque to a mechanical speedometer.
The test showed a negative result - the unit will have to be changed
To remove and install, you will need one tool: a 22mm wrench. The nut should be unscrewed with caution: the thread may become stuck due to unfavorable operating conditions. The VAZ 2114 speed sensor is replaced after cleaning the “seat” on the gearbox housing. Be sure to check the condition of the wire insulation and the integrity of the connector. Buy a branded sensor from a trusted supplier.
Before connecting the connector, it is necessary to lubricate the contacts with electrical compound. This will protect the contacts from corrosion for a long time. Be sure to secure the signal cable so that it does not fray due to vibration.
Signs of a faulty speedometer sensor
The car owner can independently determine the failure of the speed sensor. This does not require specialized education. In most cases, a malfunction is accompanied by the following symptoms:
- P0500 or P0503 on the electronic unit . In the first case, the error means loss of signal from the device. P0503 occurs when the signal supplied to the electronic control unit is unstable.
If errors occur, the cause of the breakdown may be not only the sensor, but also faulty electrical wiring. Often the transmission of incorrect data occurs as a result of oxidation of the contact pads of the connectors. In such a situation, to eliminate the malfunction, it is necessary to ring the wires and, if necessary, clean the connectors from oxidation.
- Incorrect operation of the internal combustion engine at idle. If a breakdown occurs, the speed of the power unit is unstable. Spontaneous engine stop at idle is possible. Additionally, the symptom may be accompanied by a significant increase in fuel consumption. This is due to the fact that the control unit receives incorrect data and cannot correctly select the fuel to air mass ratio.
- The speedometer or odometer does not work. The pointer needle may behave erratically or not move at all.
On cars with a cable-driven speedometer, incorrect operation of the indicator may not be associated with other symptoms. This means that the cable has broken. At the same time, the electronic part transmits correct data to the control unit.
- Decrease in engine power. The ECU cannot normally determine the speed of the vehicle and puts the engine into emergency mode.
The location of the speedometer sensor on the VAZ 2114 allows you to independently dismantle it and replace it with a new part without the use of specialized equipment.
Design and principle of operation
Three generations of speed sensors were installed on injection engines of the tenth VAZ family.
- Electromechanical with a cable stretched to the speedometer. The torque was transmitted through a gear drive from the gearbox. The most capricious option in operation and unreliable in indications.
- Electromechanical without cable. The rotation transmission was still gear-based, the electrical signal was transmitted through wires.
Both of these sensors transmitted output shaft speed using complex mechanics that often failed.
Let's look at this design in more detail.
The Hall effect is that when a concentrated electric field passes through a magnetic field, an electrical impulse occurs. To “materialize” it, a semiconductor is placed in a magnetic field, at the ends of which a completely measurable voltage appears. This impulse is the same signal that is sent to the electronic speedometer and engine control unit. The speed sensor connection diagram clearly demonstrates the principle of operation of the speed sensor on a VAZ 2114 car.
As you can see, the signal goes not only to the speedometer unit.
In accordance with the operating principle of the Hall system, one revolution of the sensor shaft generates one electrical pulse. At the same time, there are no unnecessary mechanics: only the input shaft of the device connected to the output shaft of the manual transmission.
How impulses are converted into speed and mileage
There is a known quantity: the circumference of a car tire. Of course, this system works correctly only when installing standard tires and normal tire pressure. The ECU and sensor controller take readings and convert them into mileage. That is, the odometer has already received its share of information. Divide this value by time - we get the speed of movement.
How to check the speed sensor?
You can check the functionality of the device that determines the speed using a multimeter or a test lamp. Diagnostic measures are carried out in the following order:
- Locate the part.
- Disconnect the electrical connector.
- Set the multimeter switch to DC voltage measurement mode.
- Connect one probe of the device to the contact of the signal wire. For more reliable fixation, you can use a specialized clamp.
- Attach the second probe of the multimeter to the car body. The electrical equipment of the VAZ 2114 is made according to the single-wire principle. The car body is the negative contact.
- Jack up the front wheel. Before doing this, it is necessary to eliminate the risk of spontaneous rolling of the car. To do this, install anti-roll devices under the wheels.
- Turn on the ignition.
- Rotate the wheel with different intensity as the car moves. When accelerating, the voltage should increase, and when decelerating, it should drop accordingly.
You can check the device by removing it from the car. To do this, you should forcibly rotate its moving part and take measurements in the same way. If you don’t have a multimeter, you can use a 12V car lamp.
If during the diagnostic process it was revealed that the sensor is working, you should look for a fault in the wiring. In some cases, the pointer indicator fails.
What are we seeing these days?
Upon arrival at the nearest car dealership that sells used cars, you can see a unique beauty: all the cars, as if selected, are clean, mirror-like and ready to meet their new owner. And where, and most importantly, who to look in the mouth? Unfortunately, not everything is so simple in our life. Otherwise, I could, with a great degree of confidence, rely on the speedometer readings, which actually show how far our horse has traveled, and not think about how to check whether the mileage is twisted. But, in our time, they have learned to fake horse teeth, let alone iron horses. Want to check it out? Hurry up to place an advertisement for the sale of your car, and you will immediately be bombarded with calls with offers to reduce the mileage of your car for a certain price. How do you like this?
So, it's time to move on to the main topic of our conversation.
The so-called corrective actions regarding the mileage of a car are taken through special intervention using a specialized tool or existing equipment in the vehicle components. This is done in order to change the readings of the on-board computer or instrument board in the direction you need.
Replacing DS with VAZ 2114
The part can be replaced at home. The work can be performed by a person who does not have specialized knowledge and experience. Replacement is carried out in the following sequence:
- Turn off the on-board power supply voltage. To do this, remove the negative terminal from the battery.
- Remove the corrugation. This is necessary for unhindered access to the sensor.
- Disconnect the electrical connector. The plug is equipped with two latches that prevent spontaneous disconnection.
- Unscrew the device counterclockwise.
Installation of the new part must be carried out in reverse order. In some cases, the sensor drive may need to be replaced at the same time as the sensor.
Electronic.
Speed readings are read by a special VSS (Vehicle Speed Sensor) sensor, which is located in the transmission. The sensor sends voltage pulses that operate at a frequency proportional to the speed of the vehicle. The pulses enter the multiplexer, passing through the formation block, and then into the temporary “gates”, which remain open only for a certain time. Then the counter counts the number of pulses passing through the “gate”. Information from the meter goes to the microprocessor, where it is converted into speed. The digital display receives data from the demultiplexer and decoder.
After reading and processing, the counter is reset to zero, and the next packet of pulses is received. An electronic speedometer allows you to obtain more accurate data than a mechanical one.
A car speedometer, contrary to many misconceptions, is not just a beautiful thing with an arrow and numbers that takes up half of the dashboard. A speedometer is, first of all, a device that measures the speed of your car, allowing you to comply with the speed limit and.
In some situations, you can use the speedometer; to do this, you just need to drive at the optimal speed at which the car consumes the least amount of fuel. In addition, by observing the recommended speed, for example in winter, the speedometer allows you to save your life, as well as all other road users. Well, you must admit, how would you know that you were driving fast if you didn’t have this speed measuring device? It is quite difficult to understand that you are driving 100, and not, say, 150 km/h, if the car is new, “hot”, and the road is perfectly flat. Only a very experienced motorist can accurately determine the speed. In short, the speedometer is a very important thing in a car, without which there would be chaos and “mayhem” on the road, because no one would know how “fast” it is or just a little faster...
What speed sensor is installed on the VAZ 2114?
Depending on the year of manufacture of the car, two types of sensor can be installed on the VAZ 2114. One with electronic communication with controller and speedometer. The second one has a mechanical connection to the speedometer and an electronic connection to the controller.
The market offers a wide selection of speed sensors for the VAZ 2114 from various manufacturers. The average cost is 350-450 rubles .
On VAZ 2114 cars, the speed sensor is used not only to transmit data to the speedometer, but also to communicate with the electronic control unit. The part can be replaced at home without the use of specialized tools.
Purpose
Let us immediately note that the task of this sensor includes several functions.
It is intended:
- To supply an electronic signal to the speedometer installed on the dashboard, resulting in the ability to control the speed of movement and the distance traveled;
- Based on the readings of this sensor, the electronic unit adjusts and sets optimal speed in different modes of movement;
- The sensor signals influence the operation of the idle speed sensor.
