Vehicle speed sensor VAZ 2110

The speed sensor in the VAZ 2110 (as in any other car) not only shows the current speed and records the mileage. Provides data for various primary and secondary systems. Fuel injected engines 2110 8-valve or 2112 16-valve are controlled by an electronic control unit (ECU), which requires a lot of information. In particular, thanks to the operation of this sensor, important engine functions are provided:

• the fuel mixture is formed correctly;
• the order of fuel supply is regulated;
• ignition time is set;
• idling is adjustable on the go;
• when the throttle is closed, the fuel supply is limited: this allows you to cut the fuel line from the injectors when coasting.

The VAZ 2110 speed sensor is produced by different manufacturers, the appearance may differ, but the principle of operation remains the same.

Where it is located? In the gearbox, very close to the output shaft. It is located not horizontally, as expected, but vertically. We will consider the reason in the section "principle of operation". The location is unsuccessful, the place where the wires enter the connector is in contact with the corrugation in the engine compartment.

As a result of this interaction, the cables are regularly frayed. On the other hand, it is not difficult to replace the VAZ 2110 or 2112 speed sensor, since access to the sensor is possible without using a pit or a lift.

Unfortunately, this node does not always belong to the category of reliable and requires periodic attention from the car owner.

The principle of operation of the VAZ 2110 injection motor speed meter

So why is the device in question located vertically if the axis of rotation of the manual transmission shaft is simply horizontal? The fact is that the rotating element of the device is connected to the gearbox shaft not directly, but through a transitional rotation transformer. With the help of a worm gear, horizontal rotation with a certain gear ratio is converted into the mechanical part of the speed sensor.

The end of the shaft of the electronic part of the sensor, which we see outside the gearbox, is inserted into the adapter's receiving sleeve.

The system works according to the Hall principle. On the shaft inside the housing are the moving parts of the Hall elements. During rotation, the counterpart (in the form of an inductor) generates pulses synchronized with the speed of rotation of the wheel. Since the circumference of the tire is known, the electronic module converts each revolution into distance travelled. This is how mileage counts. It remains to divide this figure by a unit of time, and we will get the speed of the car at any given time.

Important! Information for those who like to switch to non-standard tires. When installing tuning wheels and tires with an acceleration of more than 3%, you not only create an additional load on the suspension elements. The algorithm for calculating the speed of movement is violated: the crankshaft, camshaft and speed sensors are not synchronized. As a result, the ECU incorrectly forms the composition of the fuel mixture and makes mistakes when setting the ignition timing. That is, the sensor does not work in normal mode (there is no malfunction).

Why does the speed sensor fail

The reasons are mechanical and electrical. We will list each separately.

Mechanical causes include:

• gear teeth wear both on the manual transmission shaft and on the adapter - speed transformer;
• the appearance of backlash at the junction of the transformer shaft and the sensor itself;
• displacement or loss of the Hall element in the moving part;
• contamination of a pair of Hall elements inside the box;
• physical damage to the shaft or housing.

Electrical reasons:

• electronics malfunction (not repairable);
• oxidation of connector contacts;
• chafing of device cables due to improper placement;
• external interference from the injector control circuit or spark plug high voltage wire;
• interference caused by non-standard electrical devices (for example, a xenon driver or a burglar alarm unit).

Signs of a malfunctioning speed sensor

You can recognize a speed sensor malfunction by the following symptoms:

• Lack of moving speedometer readings and odometer inoperability.
• Distorted speed readings. You can check using a GPS navigator or ask a friend with a working sensor to drive parallel to you at a given speed.
• Involuntary stop of the engine at idle (these symptoms also appear with other malfunctions).
• Periodic "triple" of the motor when driving at one speed.

To rule out a speed sensor fault from other electronic faults, you can perform a quick test. You need to take a test drive and remember the feel of the car. Then disconnect the connector from the sensor and immediately go on a similar trip. If the behavior of the machine has not changed, the device is faulty.

How to check the speed sensor VAZ 2110

So, there are symptoms, but they are not clearly expressed. External examination and the integrity of the connecting cable showed that everything is in order. You can connect a diagnostic scanner in a car workshop or service and carry out a complete check of the equipment.

But most VAZ 2112 (2110) owners prefer to check with a multimeter. The pinout of the VAZ 2110 speed sensor on the cable connector is as follows:

The power contacts are marked "+" and "-", and the central contact is the signal output to the ECU. First, we check the power with the ignition on (the engine does not start). Then the sensor must be removed, energized and connected to the "minus" and the signal contact of the multimeter. By turning the shaft of the hall sensor manually, a good sensor will show voltage. Pulses can be taken with an oscilloscope: it’s even clearer.

Repair or replacement of the sensor

Repair of the sensor is not economically feasible. An exception is soldering broken wires or stripping contacts. The device is relatively inexpensive, it is not difficult to change it. So the conclusion is clear.