Why the speedometer may not work on a Niva 2121 car

The Niva car or VAZ-2121 is one of the most successful developments of domestic engineers. Having begun mass production in 1977, the car was in demand not only in the USSR, and then in Russia, but also abroad. In some countries, fan clubs of this model have even been created. The first Nivas were equipped with a three-door body and a carburetor engine with an output of 80 hp.

They rolled off the assembly line with virtually no changes in design and technical characteristics until 1993. In 1994, car enthusiasts saw a modified body and an 82.8-horsepower engine. The car was named VAZ-21213 Niva. Then the Niva VAZ-21214 appeared, on which, starting in 2002, injection power units began to be installed. In 2006, the name Niva officially ceased to exist. The car, until 2021, was called “LADA 4×4”, and now it is “Lada Niva Legend”.

From the very moment of its creation, until today, the Lada-Niva has been distinguished by the extreme degree of reliability of all components and assemblies. It is not for nothing that a huge number of these cars continue to travel on roads and off-roads, despite the fact that they came off the assembly line several decades ago. But, which is quite natural, the older the car, the more breakdowns there are. Along with the transmission, engine and body, failures of motion control systems occur, which include the speed control system.

In the article we will look at the reasons why the speedometer on the Niva does not work, using the VAZ-21213 and VAZ-21214 as an example, since these cars are the most typical and widespread representatives of the family of Tolyatti SUVs. But first, briefly about the structure of the speedometer itself and the principle of its operation.

Speedometer

The basis of the speedometer design is:

• speed sensor;
• electronic control unit;
• display.

The speed sensor receives indirect information about the speed of the vehicle, which is removed from the drive located in the transfer case. This is typical only for Niva. In other cars, the gear drive of the speedometer is installed on the output shaft of the box or on the drive of the front left wheel.

The sensor, converting the drive speed into electrical impulses (using the resulting Hall effect), transmits them to the electronic unit, which processes the signal and sends it to the display. The latter shows on its screen what the current speed of the car is. Data can be presented as numbers or a scale on digital displays, or indicated by a moving arrow pointing to the values ​​on a graduated scale on analogue indicators.

For your information. The electronic unit, receiving and processing information, sends it not only to the speedometer display, but also to the fuel supply system. The higher the speed, the more fuel will flow into the engine. It is also interesting that the program contains an algorithm that prevents the electric power steering from operating when the speed sensor is faulty.

Speedometer: false readings

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Post by Burikin-67 » April 23, 2015, 07:21

Re: Speedometer: false readings

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Re: Speedometer: false readings

Post by barmaleykin » Jun 23, 2015, 10:10 pm

Because You are not logged in. To come in.

Because The topic is archived.

stop. here everything is more complicated: the cable is not inserted into the solder, I also thought so in my stupidity :) but the cable is inserted into the speedometer drive pipe! and is screwed with the gearbox mounting nut onto the thread.

Why does the speedometer not work?

There may be several reasons why the speedometer on the Niva suddenly stopped working.

Let's list the main ones:

1. The malfunction may have occurred due to a broken speed sensor.
2. Secondly, the car wiring is damaged or the contact in the electrical circuit is broken.
3. The third reason, sometimes, is the speedometer needle getting stuck in a certain position.
4. A problem with the electronics of the control unit can also cause a speedometer malfunction.
5. Incorrect installation of speed control system parts after they have been replaced or removed.

Chevrolet car repair manuals and tips

Guide to replacing and repairing a speed sensor on a Chevrolet Niva

Speed ​​sensor on a Chevrolet Niva: purpose, replacement and repair

The speed of a car has long been measured not mechanically, but electronically. This measurement is based on the principle of the Hall effect, using a special device. The Chevrolet Niva is equipped with the same electronic device, which accurately reads the speed developed by the car. This device is necessary so that the driver can control the speed of movement. Let us analyze in more detail the design of this sensor, its operating principle, and possible malfunctions. We will also consider how to replace it on a Chevrolet Niva.

Part appearance

Each car has a speedometer in its design, which displays the speed of movement of the vehicle. But the speedometer is only a display of useful information; the main function of indicating the speed of movement is performed by the sensor. If it malfunctions, further travel becomes a pain, especially on city highways, where it is necessary to maintain the speed of movement.

Therefore, the main function of the device is to read information about the movement of the vehicle. Indirect functions of the device include:

possibility of rational fuel consumption; regulation of traffic according to road markings and signs; makes it possible to regulate speed in order to avoid fines.

It is possible to drive a car without this part, but it is quite difficult.

There are two types of speed sensors:

1. Mechanical or optoelectronic. It works by transmitting the number of revolutions of the box shaft using a cable. 2. Electronic or cableless. Actually, that’s what we’ll be talking about.

Important! It is imperative to purchase the product only for your car model.

Operating principle of the sensor

An electronic device for reading vehicle speed is installed on a Chevrolet Niva SUV. The sensor works on the principle that was founded by the American physicist Edwin Hall. The essence of the effect (and operating principle) is the reading of electromagnetic pulses by a sensor, which are sent to the controller for subsequent processing. One kilometer of the vehicle's travel distance is equal to 6004 electronic pulses from the sensor. When the car moves faster, the frequency of pulse transmission increases. The controller, in turn, measures the intervals between each pulse and displays them on the speedometer in a form understandable to humans.

Device placement and design

On a Niva Chevrolet car, the sensor is installed on the gearbox. Due to the rotation of the box shaft, electromagnetic pulses are generated inside the device.

product placement on Chevy Niva

Structurally, the sensor consists of a steel or plastic housing, internal elements and conductors. It is attached to the gearbox directly to the shaft. Inside there is a ferromagnetic core that rotates when the car moves and creates electrical impulses. Pulses are sent through a conductor to the controller, which is located on the speedometer.

Sensor appearance

Important! The product is a fragile material, so you should be careful when carrying out repair work.

During the operation of a Niva Chevrolet, interruptions or breakdowns of the speed sensor often occur. There is no need to rush to purchase a new sensor and replace it. First of all, you need to find the cause of the problem and then make a decision. So, the causes of malfunctions can be:

1. Electrical circuit break; 2. Oxidation of contacts; 3. Violation of the integrity of conductor insulation; 4. Damage to the integrity of the device or wear of internal mechanisms.

Important! To determine the malfunction, it is necessary to carry out testing actions!

Checking the Chevrolet Niva speed sensor for faults

There are two ways to check the sensor for faults, which we will consider separately.

First way. To carry out the test you will need a multimeter.

1. The sensor is removed (the removal and replacement process will be described below). 2. The positive probe of the device is connected to the pulse contact of the sensor. 3. The negative probe of the device is connected to the “ground” of the car. 4. A tube is put on the sensor shaft to allow rotation. 5. The multimeter is set to measure low DC voltage. 6. We begin to rotate the mechanism shaft. When rotating, the device will display the value of the induced voltage, and as the speed increases, the indicator will increase.

If such a process is observed, then the speed sensor is serviceable, and the cause should be looked for elsewhere.

Second way. Does not require dismantling.

1. Use a jack to lift the front of the car so that one wheel is suspended. 2. A multimeter is connected to the sensor terminals. 3. The wheel rotates and the appearance of pulses is detected. If voltage is induced, then the device is in working order.

The reason is the sensor

In principle, this is one of the few speedometer malfunctions that you can try to find and fix yourself. Not counting the jammed arrow and the torn cable. All other problems, including those with the electronic control unit and digital display, are best resolved at specialized service stations.

The first sign of a speed controller failure will be the speedometer stopping or its readings being incorrect. But the fact that the speedometer has stopped working due to the speed sensor can be determined by other signs:

1. The engine constantly stalls when idling. This does not depend on whether the car is standing or rolling.
2. The car cannot accelerate due to loss of power.
3. Fuel consumption in all driving modes has increased sharply.

The reason that a faulty sensor affects engine performance so much is that it is included not only in the speedometer circuitry, but also in other systems.

You can check the functionality of this device using a voltmeter. It is more convenient to do this if you remove the sensor. But you can check it in its original place, without dismantling it. In any case, you need to gain access to his contacts. On a working sensor, the voltage readings will increase along with the increase in the rotation speed of its axis.

For your information. Rotation of the sensor core, which has not been removed from the vehicle, can be achieved by turning the suspended drive wheel.

Before checking and changing the sensor, which breaks quite rarely, you need to make sure the contacts are reliable. Often the problem lies in their oxidation or excessive contamination, since most Niva cars are operated in extreme conditions. Typically, the problem with a non-working speed sensor is solved after checking each contact, cleaning them and lubricating them with a protective compound.

speedometer Niva Chevrolet

To do this, there is a panel self-diagnosis procedure. The checking process is as follows: Turn off the ignition and press the daily mileage reset button.

Using a transfer case on a Chevrolet Niva.

Do not release the button and turn on the ignition. In this case, the arrows on working instruments should move three times from zero to the maximum division.

Everything is clear here - if the speedometer refuses to fulfill the test conditions, the problem is either in the device itself or in the tidy board. Most likely, you will have to change the board assembly.

Checking the contacts of the speedometer and speed sensor There are not many contact blocks in the speedometer circuit. It often happens that vibration causes the block moving from the common bundle of wires to the dashboard to move. To eliminate the possibility of losing contact in this place, you will have to move the device away and remove and insert the chip on the back of the panel board several times.

Sometimes the block may simply be installed skewed, then the contact may be inconsistent or absent altogether. The location of the speed sensor is schematic. If this does not help, you will have to look for the contact connector on the speed sensor.

As we said, it is located on the transfer case housing and its connectors often suffer from water and reagents that are sprinkled on the roads.

The contact needs to be disconnected and its condition assessed. In addition, the wires themselves that go to the speed sensor often come under attack.

And the location of the sensor is not entirely successful; the wires can simply be torn out by a snag. Checking the speed sensor The design of the speed sensor is simple - it is a metal or plastic case, a ferromagnetic core and a winding in which the rotor rotates, generating an electrical impulse - the faster the sensor roller rotates, the greater the impulse, the further the speedometer needle deviates from zero.

Most often, if there are no visible abrasions in the wiring, then the speed sensor is to blame.

On-board network malfunction

Often, this is precisely the reason why the speedometer has stopped working. After all, all information in modern devices is transmitted through electrical wires. A break or short circuit may occur in the vehicle wiring. A multimeter can detect this. If you have the skills to work with this device, you can try to find and fix the problem yourself.

Before you start searching for a break, you need to carefully inspect the wires to visually detect damage. After this, the tightness of the terminals is checked. If everything seems intact, the search begins using special equipment:

1. The multimeter is set to ringing mode.
2. The probes are attached to the ends of the area being tested.
3. If the wiring is intact, a beep will sound. Its absence will mean that the break occurred in the location being tested.

To check for a network short circuit, the multimeter is also set to ringing mode. Before starting work, the wire is disconnected from the vehicle's electrical circuit. And, if in the case of a break, the signal indicated that the cables were in good condition, then the sound of the multimeter will now show where the short circuit occurred.

As a rule, eliminating problems with the wiring and replacing the speed sensor resolves the issue with the performance of the speedometer. But, if this does not happen, you need to contact specialists as soon as possible. After all, driving a car with inoperative speed control not only harms its technical condition, but also poses a real danger to the life and health of all road users.

Diagnostics

Troubleshooting begins by disconnecting the wiring block from the speed sensor harness and checking them using a test light.

To make a control light bulb, you need any car lamp that can operate at a voltage of 12 V, and two wires about 1 meter long each. One of the wires is attached to the positive terminal, the second - to the negative terminal of the lamp. The resulting device also includes a Krona battery.

To carry out the test, one wire of the warning lamp is attached to the ground of the body or battery, and the second is made with short, frequent touches to the middle contact of the DC connector. If there are no faults in the connector-speedometer section, the speedometer needle will slightly tremble or rise. If the needle shakes, the answer to the question why the speedometer does not work can be considered found - the speed sensor requires replacement.

In cases where the needle’s response to tapping on the central contact of the block cannot be detected, it is necessary to “test” the speedometer power circuit. The procedure is carried out using a multimeter (multitester), or by using the same light bulb - a control.

If the tester in the “continuity” mode indicates a violation of the integrity of the circuit, further troubleshooting is carried out in this direction. It is necessary to check the fuses, the connection points of the wires, and their integrity inside the insulating braid.

The search area can be reduced by gradually “ringing” individual sections of the circuit. On model 2114 and other VAZ products, the cause of speedometer failure is often oxidation of the “mass” contacts attached to the car body.

In cases where the speedometer needle does not work, but there is no evidence of malfunctions in the electrical supply circuit, a logical conclusion is drawn about the malfunction of the device itself. Additional testing can be done by temporarily installing a known good instrument panel.

Relays and fuses Lada 4×4 (VAZ 21214, 21314)

December 23, 2015 Lada.Online 845 741
Modern AvtoVAZ SUVs use injection power units. If a malfunction is detected in the electrical equipment of the car, you should first check the serviceability of the fuses and relays. Next, we will show where the mounting block is located (fuse box or black box), as well as the location of the elements inside it.

Location of fuse and relay blocks Lada 4×4

The main part of the fuses is located in the interior of the Lada 4×4 under the panel to the left of the steering column. Total 4 blocks:

1 — engine control system fuse box; 2 — windshield wiper relay; 3 — fuse blocks; 4 — relay block of the engine control system.

The fourth relay block is located above the gas pedal.

Main and additional fuse blocks

These two blocks are connected to each other. There are 10 fuses in the upper block, and 6 in the lower one. Markings from left to right:

F1 (16A)	Heater fan, rear window defroster, rear wiper and washer system, windshield washer pump
F2 (8A)	Steering column switch, windshield wipers, hazard warning lights, breaker relay (in turn signal mode), reverse light, instrument cluster (coolant temperature gauge, fuel level gauge, tachometer, warning lights: turn indicators, differential lock, parking brake, emergency condition of the working brake system, insufficient oil pressure, fuel reserve, battery charge)
F3 (8A)	Left headlight (high beam), high beam indicator lamp
F4 (8A)	Right headlight (high beam)
F5 (8A)	Left headlight (low beam)
F6 (8A)	Right headlight (low beam)
F7 (8A)	Side light lamps in the left front and left rear lights, license plate lights, control side light lamp

Additional block:

Additional fuse circuits in the Urban package:

Fuse number and rating

Protected circuit

Main unit

Additional block

Engine control system fuses

It is located on the left side of the body, under the instrument panel, next to the diagnostic block. Consists of four fuses: