Why does the needle of the speedometer twitch?

Often, electric circuits drivers practicallydo not pay due attention. Wires from the moment of purchase of the car almost never change. As a rule, this is not necessary, as long as everything works. But sooner or later there comes a time when the wiring starts to pour. The arrow of the speedometer twitches, the instrument panel lights are floundering, etc. All this is solved, so let's deal with this issue in more detail.

What do you need to know?

Often, the problem with the speedometer refers toelectronic malfunctions. Although much depends on the car. For example, if the arrow of the VAZ-2107 speedometer twitches, then it's not necessarily the case in the wiring. The speedometer in this car is of a mechanical type, there is at least a minimum of wires. Therefore, very often the problem is a cable that has lost tension.

At the same time, the case may be in defectivespeed sensor. Many motorists test its performance first. It's much easier than dismantling the dashboard, repairing the malfunction and reassembling it. Let's look at the same in more detail with the main malfunctions of speedometers on some brands of cars and consider methods for their elimination.

Problem with the speed sensor

In order to understand the question of how,why the needle of the speedometer jerks, it is necessary to become more familiar with the design of the car. For example, the domestic classics did not have a speed sensor. The system worked like this. At the checkpoint was located the motor (drive), which, during the car's movement, twisted a cable going to the speedometer.

If the motor was out of order, then on the panelthe arrow at all "died" and always showed "0". But most modern cars are equipped with a speed sensor, which is installed in the gearbox. It practically without error determines the speed mode and transmits data to the speedometer by means of wires. From the same wire and sensor, the data also come about the distance traveled, that is, to the odometer.

Typical malfunctions

Talk about the reliability or unreliability of thissensor is not necessary. On some cars, it works during the entire lifetime, but on others it often breaks down. Nevertheless, there are a number of typical problems that motorists face:

• Failure due to old age. Every electronic device, regardless of quality, has its own resource. Therefore, it can fail at any time.
• Mechanical effect. Simply put, damage to the sensor housing or wiring. If any work was done to remove and install the sensor, it is likely to damage it.
• Oxidized, parched or broken wires. Also, the trunk works out its own, if it has not changed for a long time.
• The sensor does not fit the given model of the car. In this case, do not rely on correct readings of the speedometer.

Troubleshooting methods

Usually the working capacity of control devicescan be restored by replacing the speed sensor. As an example, consider the car "Hyundai Accent". The arrow of the speedometer twitches - we go to buy a new speed sensor in the store. With a large mileage of this brand of cars, this is quite a typical problem for him, which many motorists face. If the box is mechanical, then the problem is most often solved by replacing the cable. Lubrication with VD-40 also helps, but this is more of a temporary solution, so in the future the problem can return.

As for the automatic transmission, there are installedsensors that often fail. Change them will not be difficult. Let's see how to do it and what we need to do the work.

Replacing the speed sensor

If the arrow of the VAZ-2107 speedometer twitches, thenit is necessary to replace the cable or worn out gears, whose faces have already worn out during the operation of the car. This rule is practical for all cars that are equipped with manual gearbox. The speed sensor is installed in the automatic box. Let's look at the example of "Accent" consider the replacement process.

For the work we need to buyThe original speed sensors cost 800-900 rubles apiece. The tool needs a key on the 10 and 12, as well as the corresponding heads. There are two sensors in total. The first is located on top of the box, the second is on the bottom. To get to the top, you need to dismantle the air filter box and remove the battery with the platform. After that, use the key for 10 to unscrew the old one and install a new one. The lower sensor is behind the left wheel. To get to it, you need to remove the protection of the box and the front part of the fender cover.

Wrong wiring

As already noted above, the wires with timeoxidize, bend and just crumble. In the end, this leads to the fact that the contact completely lost, which before it appeared, then disappeared, which led to an incorrect operation of the speedometer.

This problem can be solved in several ways. The simplest is to solder the wires and put them on a heat shrink. The problem may arise elsewhere, but this may not happen. The second method is to replace the entire braid. A more laborious and complex method, but as a result - the normal operation of the wiring for a long time. Also it is necessary to understand that if the wire is bare, it can shorten by weight. In this, too, there is nothing good, so if you noticed this, then it's worth trying to fix the problem as soon as possible.

The arrow of the speedometer VAZ-2109 is twitching

Often a problem will bedismantling of the instrument panel. It takes a long time, although almost everyone will cope with this task. To perform the dismantling, you need to get the radio and cigarette lighter, emergency lamp and unscrew all the necessary fasteners. Now you can proceed with immediate repair.

If the needle of the speedometer twitches when typingspeed, then, most likely, the case in the drive, which broke down. Therefore, you need to remove the drive, gears, and seals. The latter must be replaced with new ones. Next it is desirable to carry out the defect of the gears. If the faces are lapped on them, then we change them.

In addition, it is advisable to check the cable. It is likely that it touches something during the ride, which causes the jumps of the arrow of the speedometer. If necessary, replace and lubricate the cable. Then we perform the assembly.

Atypical breakdowns

If the arrow of the speedometer twitches (2109 is a VAZor another model - it's not important, a breakdown of this type is inherent in many cars), and the above method did not help, that is, several more options. One of them is the jamming of the arrow in a certain position. Therefore, when dialing speed devices can display normally, but at some point there will be a jump. Solve the problem by disassembling the instrument panel and repairing the speedometer. It is likely that you will need to remove the arrow and lubricate it or change it to a new one.

Another atypical failure is failuregear after twisting the run on a mechanical speedometer. It occurs very rarely and says that the masters correcting the run were not too mean with the car. But on the electronic speedometer when twisting the run, the system can be locked, and the "Chek Engin" error appears on the dashboard. Lastly, it is worth looking at the on-board computer, but this only applies to electronic systems.

How to replace the cable

Over time, the cable decays and graduallybegins to fail. The first time the problem manifests itself in the form of the jerks of the speedometer and tachometer. If you do nothing, the devices will soon and completely stop showing the speed of the car and the mileage. To solve the problem, it is necessary to drive the car to a pit. On the side of the engine compartment is the drive cable. After disconnecting the protective cover, unscrew it with the usual carabiner wrench. Now we can disconnect the wire.

It is desirable to pre-disassemble the paneldevices. This is due to the fact that after we detached the cable from the drive, it must be disconnected from the speedometer. We unscrew the nut and take out the wire through the engine compartment. In this case it is desirable to remember how it passed, so that later there were no problems with its installation. Two types of instrument panels were installed on the VAZ-2109: low and high. Accordingly, the length of the cables is different, so when you buy with you it is desirable to have a sample, so as not to be mistaken.

A few important nuances

Here we are, in fact, figured out why it cantwist the needle of the speedometer. As you can see, there can be a lot of reasons. But, faced with such a problem, does not necessarily immediately go to the SRT. Malfunction often can be eliminated independently, of course, if there is time and desire.

Ironically, with the electronic systems in thisThe case is much simpler. In most cases, all ends with a banal replacement of the speed sensor or wiring. Another thing is that this sensor for some cars is worth a lot of money. In this case, you can try to find a decent analog with the help of Internet directories. But openly Chinese products, which beckon its low cost, it is better to bypass. After all, such a sensor can please the owner of the car with correct work for a short time, or even not work right after installation.

Finally

The problem of mechanical speedometers most oftenis the critical wear and tear of the main mechanisms. For example, under the influence of high humidity and salts, the cable rotates. If at some point the speedometer stops showing, then the case is clearly in the cable. In fact, the twitching arrow is not uncommon. Many motorists prefer not to pay attention to this problem at all and leave everything as it is. It is much worse when the revolutions begin to float at idle.

As for some modern carsknown brands, for example, "Mercedes" or "Audi", then it is sometimes difficult to do something on your own. In this case, it is still better to visit dealers or service stations. But to repair the old "Volkswagen" or VAZ will not be difficult even for the beginner. The main thing is to thoroughly approach the solution of the problem and have a minimum of the necessary instrument. In the most neglected cases it makes sense to change the speedometer drive, but this only applies to mechanical options. This is similar to replacing the speed sensor, but somewhat more complicated and expensive. That, in fact, is all that you need to know about the problem and the methods of its elimination.