Mechanical speedometer does not work, causes of malfunction

Replacement

Replacing the VAZ-2109 thermostat is very simple. To do this you need:

• Allow the engine to cool completely.
• Drain the antifreeze through the drain window at the bottom of the radiator.
• Using a screwdriver, loosen all 4 clamps holding the pipes.
• Remove the thermostat.
• Install the new part by securing all 4 clamps and adding coolant to the radiator.

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After adding fluid, you must start the engine without closing the cap of the expansion tank. This will allow all the air to leave the cooling system.

There are many types of thermostats on the market. The most suitable for the VAZ-2109 is the thermostat from 2110 with an 8-valve engine. It is slightly smaller than the original “nine”, it can be disassembled and only the valve mechanism can be replaced. This unit will not require any modifications or corrections. The thermostat from the VAZ-2110 is more reliable and practical. After installing it, the car interior heats up faster, and general engine warm-up is carried out in a shorter period of time.

How to check the speedometer shaft?

Usually, to check the functionality of the shaft, it is enough to drive a couple of tens of meters. Start the engine and drive 20–30 meters and observe the behavior of the end of the shaft. If the tip is motionless, you need to lift the hood cover, unscrew the nut that secures the shaft. If only the shell of the part gives in, then this will indicate only one thing - a shaft break has occurred. In this case, you will have to remove the remaining tip from the drive. For this job you will need pliers.

Another development of events is also possible if both the shaft and the shell fail, and this will indicate that there are simply no edges at the tip of the shaft. Regardless of the reason for the shaft failure, it will have to be replaced.

Often the need to change the drive arises due to wear of paired gears. In order to solve this problem, you do not have to remove the gearbox. To solve the problem, it is enough to have an inspection hole or overpass.

The first step is to unscrew the bolt that secures the drive housing to the gearbox. After this, the housing is removed, then the gears. The latter must be replaced. In order to choose the gears that are suitable for your car, just compare the new ones with the old ones, the number of teeth should be the same.

If there is oil on the housing, it would be a good idea to check the O-ring and replace it if necessary. The drive elements are washed using clean kerosene.

The order of assembling the unit is reverse.

If problems occur when installing a new panel

A “twitching” needle during ignition indicates that power is coming to the speedometer. Possible problems could be:

• incorrect connection of wires;
• there are breaks in the wiring - check the integrity of each wire separately;
• There are problems in the device itself - burnt out tracks or the speedometer drive.

By the way, the mere fact of replacing the sensor does not yet indicate its performance. VAZ sensors often turn out to be “dead” immediately after purchase. Ideally, ask your friends for a similar sensor that is known to work.

Speed ​​sensor VAZ 2109

The speedometer operating system is quite simple. The speedometer sensor produces a signal. Further along the wiring it is duplicated and simultaneously goes to the ECU and the dashboard. Next, along the tracks on the dashboard board it gets to the speedometer mechanism - the arrow rotates to the desired angle.

The fault may be in any of these elements. Always pay special attention to the chips (contacts oxidize, measure with a tester, spray with a wedge, bend if necessary).

Just like any other old car, there are problems with the wires - they burn out, break under the insulation (check with a continuity tester). You can use a multimeter or a universal probe that “can” find plus, minus and absence of a signal. A 12V screwdriver, which detects only power, is an inferior assistant.

Procedure

Now let's figure out how to remove the drive when the speedometer on a VAZ 2109 does not work:

• To do this, release the cross member that secures the gearbox to the body, give back the nut that secures the drive
• Pry off the drive housing with a flat screwdriver (as in the photo below)
• By pressing the gearbox to the side (for example, with a piece of pipe) from the drive, we pull the drive out of it
• Then we check its serviceability
• To do this, twist the gear and see whether the groove for the speedometer cable begins to turn or not
• If the groove does not turn, then replace the speedometer drive
• When going to the store for a new drive, it’s better to take the old one with you as a sample just in case (you can confuse the number of teeth on its gear)
• And if you install a “foreign” (not the one you need) drive, then in no more than 100 meters it will break the box cover, because a mismatched gear pitch will simply turn the entire drive outward and result in serious damage to the gearbox
• To be able to use this gearbox in the future, it will be necessary to replace its rear cover and completely change the oil
• If the old one suddenly pours out, there will still be fragments and crumbs of the housing left in it, which can subsequently fall on a gear tooth or clog the oil channel

Now that you know how to determine what the reason is if the speedometer needle suddenly starts jumping and fix it with your own hands.

Drive repair

We only considered replacing the drive, if the speedometer does not work in the VAZ 21093, sometimes this is easier and cheaper to do:

• The speedometer drive is removed, as a rule, to replace its housing, or the sealing ring from under which lubricant flows, or the drive gear itself
• It can be removed without dismantling the gearbox assembly; for this purpose it is better to drive the car onto an overpass, inspection hole or lift

The repair procedure will look like this:

Using a socket wrench, unscrew the bolt that secures the drive housing, pry it off with a screwdriver, then remove it

Unscrew the drive nut, remove it, then pry off the housing with a flat screwdriver and remove the drive

Now we can remove the driven gear. This gear is made of plastic, so it is important to carefully inspect it and if you find signs of wear, replace it immediately

We inspect the condition of the rubber seal (shown by the arrow), then remove and inspect the plastic gear

In addition, it is important to pay attention to the condition of the mounting socket, where the tip of the flexible rod (cable) of the speedometer enters. The socket should not have licked corners or be broken, otherwise such defects will be the reason for replacing the gear. It is also worth paying attention to the condition of the box body in that place , where our drive is installed. If traces of lubricant leaks are visible, then it will be necessary to replace the rubber ring of the drive seal, which is located on its body. To remove it, you will need to remove the driven gear, then push the sealing ring out of the groove. All parts are then washed in clean kerosene

Of course, no one has canceled the service station services, if you are too lazy to tinker, although tinkering is probably not an applicable expression here (it only takes 10-20 minutes), and the price of their services suits you, then decide for yourself.

Replacing the cable

Almost everywhere, car owners are faced with the problem of speedometer failure, which is often caused by a faulty cable. To replace the cable, it is not at all necessary to go to a car service center, because you can easily cope with this task yourself, our instructions will help with this. So:

Go down the car (on a pit or overpass), then you need to unscrew the cable from the drive of your speedometer, located on the side of the engine compartment, move the rubber cover up, and unscrew the nut on the cable. After that, disconnect the cable. To disconnect the cable from the speedometer, you must first remove the instrument panel from dashboard In this case, if your car has a low dashboard, then unscrew two bolts and carefully remove the visor, squeezing the spring-loaded clamps with your fingers. Then you can remove the instrument cluster. If the car has a high dashboard, then first you will need to remove the trim, then unscrew the unit instruments Then you should unscrew the cable nut from the speedometer from the back side, and pull out the old cable through the engine compartment, remember how it went through. Because the next step you will have is laying (pulling) the new cable. Inserting the plug into the compartment bulkhead will be much easier , if you pre-lubricate it with oil, for example Litol

The device and principle of operation of the speedometer

The speedometer drive is a set of mechanisms designed to transmit information about the speed of the car to the speedometer dial. On the VAZ 2109, this drive is made in the form of two gears (driven and driven), which are mounted on the secondary shaft of the gearbox, as well as a flexible shaft.

When the secondary shaft rotates (the car begins to move), the drive gears receive torque and transmit it to the flexible shaft, which, in turn, being connected to the speedometer needle, causes it to show the necessary information on the dial.

Depending on the vehicle modification, the flexible shaft may have different lengths. This is due to the fact that the first “nines” had a low-mounted torpedo, which means the shaft was shorter. Only the latest car releases that underwent modernization received a torpedo with a higher location, which forced designers to produce a longer flexible shaft.

Troubleshooting

To detect a breakdown, you need to detach the flexible shaft from the gearbox. Here, using pliers, you need to unscrew the nut on the cable wrap and detach the shaft from the gearbox. Afterwards, clamp the shaft shank into the drill holder and connect the latter. If the sensor scale deviates, this means the mechanism is working; if not, the device should be replaced.

If the meter is working, you should carefully examine the tip of the flexible shaft. The tip must have the correct 4-sided section. If they are damaged and the tip has a rounded shape, then the shaft needs to be replaced. If the edges are damaged, the shaft slips in the drive and a typical clicking sound is heard, as a result of which the VAZ 21099 speedometer needle twitches.

If the shaft attachment is appropriate, then the sensor shaft drive needs to be replaced. In addition, if there is an electronic meter, you should thoroughly examine the wires connected to the device for fractures or breaks.

Why did the speedometer on the VAZ 21099 stop working?

VAZ 21099 is a very popular car in Russia. The reliability of this car, as everyone knows, leaves much to be desired, so car owners quite often encounter malfunctions of their VAZ 21099. All the problems of this car have long been studied and described. It often happens that malfunctions occur in the car’s speedometer.

Due to problems with speed detection, you may receive tickets for exceeding speed limits, or you may experience problems with shifting gears if you are a novice driver or are accustomed to determining when to change gears using the speedometer. In this article, we will study the causes of the problem and find out how to repair the speedometer.

How does he work

The operating principle is based on the following. For each kilometer traveled, the speed sensor (DS) transmits a certain number of pulses to the controller.

The number of impulses transmitted per 1 km is 6004. The faster the car moves, the faster the impulses are transmitted. Due to this, the controller determines the speed based on the time interval between received pulses.

It should be noted that the DS also has an additional function that allows you to partially save fuel for the VAZ 2109. When coasting at a speed of more than 20 kilometers per hour, the controller, relying on data from the DS, does not open the fuel supply.

Location

The location of the speed sensor is the same on almost all cars of the AvtoVAZ family.

DS location

How to repair the speedometer drive

Now we will talk in more detail about dismantling and repairing the drive. It often needs to be repaired if the O-ring begins to leak oil. To repair this unit, follow the instructions:

1. Using a socket wrench, unscrew the bolt holding the speedometer drive housing.
2. Then pry it up with a screwdriver and remove the drive.
3. Inspect the driven gear; it is made of plastic and may show signs of wear. In this case, it is best to replace the part.
4. Check the rubber seal. If signs of wear are visible on it, replace it.
5. Then evaluate the quality of the seat for the cable end. It should also not be worn or damaged.
6. Look at the drive mounting location on the gearbox; if there are oil leaks there, the O-rings must be replaced. They are located on the body.
7. If you decide to replace these rings, you will need to first remove the driven gear and then push out the seal.
8. Soak these parts in kerosene. If they are not worn out, replace them. Also wipe the remaining parts with kerosene and put them in place.

The total time for repair and dismantling of this VAZ-2109 unit will take about 30 minutes.

Purpose of the speedometer and possible causes of problems

Before you figure out why the speedometer needle jumps on a VAZ 2109, you should understand what is where and what it is intended for. Speedometers are designed to convert the rotational speed coming from the drive shaft to the speedometer sensor into an indication of the speed of the vehicle and, in addition, the number of revolutions that the speedometer sensor drive shaft makes are converted into readings of the trip meter (kilometers) traveled by the car. But when the speedometer needle jumps or even spins as it wants, or may even freeze in one position, it means that there are problems with the speedometer mechanisms and there may be several reasons for this. This:

• A breakdown inside the speedometer itself (see VAZ 2109: how to properly repair the speedometer)
• Broken or damaged speedometer cable
• The speedometer gearbox (aka drive) is broken

Diagnosing the malfunction

It is important to first understand why the VAZ 2109 speedometer does not work:

• To find the reason, we climb under the car from an inspection hole, overpass or lift
• If you don’t have any, you can get by this way - just slightly lift the car, put a reliable safety net (thick wide wooden blocks - you can’t use bricks), then unscrew the nut securing the speedometer cable
• We call an assistant and with his help we check the serviceability of the speedometer and its cable
• While you are turning the speedometer cable from below with your hand (having disconnected it from the drive) in one direction and then the other, an assistant in the cabin monitors the arrow - if at the same time the speedometer arrow jumps, then the cable and speedometer are working, and you should check the drive
• However, there are cases, even though the arrow jumps, there may still be a problem in the cable, it has fluffed up inside the braid and sometimes touches it

Mechanical speedometer

There are significantly fewer problems with this system and the methods for eliminating them are simpler. Symptoms of problems are as follows:

1. The arrow works with jitter, jumps or does not work at all.
2. The noise of a flexible shaft can be heard in the cabin.
3. The arrow does not rise above a certain level.

All these symptoms require a thorough check.

Examination

It is easiest to start diagnosing the mechanical system of the VAZ-2109 speedometer with the drive. To do this you need:

1. Unscrew the drive from the manual transmission housing.
2. Inspect the gear on the rod. If its teeth are broken or worn out, the drive will have to be replaced with an analogue.

3. If the teeth are in order, then you need to unscrew the nut holding the cable. Next, the tip of the flexible shaft and its seat in the drive are visually inspected. The tip should be square, as should the drive recess. If worn edges of the cable or drive are noticeable, the parts require replacement.

4. The absence of wear on the cable and the deepening of the drive will require checking the integrity of the flexible shaft. To do this, you need to pull it using pliers. If the cable comes out of the guide casing, it means that it is broken and requires replacement. An intact cable can also cause a malfunction. Its steel wires break off and cling to the walls of the casing. The presence of such damage is also considered a reason for replacement.

The absence of a cable break will indicate a malfunction in the instrument panel itself. It will have to be dismantled in order to check the sections of the flexible shaft and its seat.

A common cause of intermittent failure is the cable getting stuck in the casing. It's all due to the hardening of the lubricant. Before installing a new cable, it must be lubricated with a compound with a solidification temperature threshold of at least −20 degrees. The lubricant also hardens due to prolonged vehicle inactivity. Dust and dirt mix with the lubricant, which leads to disruption of its composition.

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Installing a speedometer on a VAZ 2109 car

The purpose of the speedometer is to inform the driver about distance and speed. It also defines the composition of its units - a counter showing the mileage of the car, called the odometer, and the speed - the speedometer itself. A broken speedometer is a very unpleasant breakdown. Traffic cops can be penalized for speeding and difficulty changing gears correctly, especially around corners. Repair of the VAZ 2109 speedometer is carried out independently.

Symptoms of speedometer defects:

• The numbers don't exactly hit the shelf, but eventually they stop working.
• The speedometer begins to display the wrong vehicle speed.
• Sensors burn out.

To repair the VAZ 2109 speedometer, you need to remove the front panel:

• Unscrew the beard. To do this, tighten two screws on one of the panels.
• The top panel releases three clips and turns off the side lights, hazard lights and low beams.
• The radio is removed, the cigarette lighter is turned off.
• Unscrew the two screws securing the panel and the speedometer cable. Three gaskets removed and panel removed.
• The screws holding the speedometer unit are loose.

If you have exceeded the speedometer, you must do the following:

• Slide the pointer over the stop.
• Tape a piece of construction tape to the bottom of the scale.
• The marker is placed at the top of the arrow.
• Using a ruler, the distance on the device is measured from zero to 10 km per hour. Its value is 0.7 mm.
• The required distance on the adhesive tape from the previously placed mark is measured and the mark is placed again.
• The speedometer needle is removed and installed so that its lower position drops to the second mark.

How to remove the instrument panel

It's okay if the testing mode does not produce results. On some cars it is not there at all, and therefore there are other ways to repair the speed sensor. Here's one of them: drive the car into the garage, set it to the parking brake. After opening the hood of the car, disconnect the battery from the wire with the minus sign. This will allow you to avoid short-circuiting the on-board network. Now you need to pull out the instrument panel. Remove the trim, and then carefully unscrew the steering wheel. After this, you need to remove the switches that are located under the steering control. Having done the above, you need to unscrew all the self-tapping bolts that hold the instrument panel in place.

Having completed all the above steps, you can remove the dashboard on which the instrument panel is mounted. To do this, you need to grab it by the edges and then pull it slightly in your direction. Now disconnect all the wires attached to the dashboard. But before you disconnect them, label each wire. This is necessary in order to avoid mistakes when putting the entire structure back together. After disconnecting the wires, pull out the dashboard.

The instrument panel is attached to the dashboard with several bolts. Unscrew them to disconnect it. Now you need to remove the glass, which is held in place with glue-sealant. The place that connects the glass and plastic needs to be heated with a hair dryer. After completing these steps, you can easily detach the glass.

If the panel worked before

The check is essentially the same, but you can exclude an error in connecting the wires from the list of possible faults when switching to a new chip.

If you have a VDO device, on our website you can see how to do its self-diagnosis. If not, purchase a “lace” or have it diagnosed at a car service center. Sources of errors can also show which way to dig.

There is a feeling that in your case the problem lies in the speedometer mechanism itself or the tracks on the panel. Disassemble the panel yourself - call the roads, check the mechanism (continuity, check the integrity of the gears in the speedometer drive or other problems - the unit is quite complex, there are many sources of malfunctions) - or take it to a good electrician.

Also on amateur radio forums you can find diagrams of simulators of the speedometer sensor. Assembling this circuit will be useful for checking the operation of the speedometer. Without it, the dashboard will have to be constantly placed on the car and removed back.

How to repair the speedometer drive

Now we will talk in more detail about dismantling and repairing the drive. It often needs to be repaired if the O-ring begins to leak oil. To repair this unit, follow the instructions:

1. Using a socket wrench, unscrew the bolt holding the speedometer drive housing.
2. Then pry it up with a screwdriver and remove the drive.
3. Inspect the driven gear; it is made of plastic and may show signs of wear. In this case, it is best to replace the part.
4. Check the rubber seal. If signs of wear are visible on it, replace it.
5. Then evaluate the quality of the seat for the cable end. It should also not be worn or damaged.
6. Look at the drive mounting location on the gearbox; if there are oil leaks there, the O-rings must be replaced. They are located on the body.
7. If you decide to replace these rings, you will need to first remove the driven gear and then push out the seal.
8. Soak these parts in kerosene. If they are not worn out, replace them. Also wipe the remaining parts with kerosene and put them in place.

The total time for repair and dismantling of this VAZ-2109 unit will take about 30 minutes.

Signs of breakdown

The car itself can tell you that the DS is out of order. To do this, you just need to pay attention to the characteristic signs of such a breakdown:

• The speedometer does not work at all or provides incorrect information about the current speed;
• Idling behavior is unstable;
• Gasoline consumption is increasing;
• The motor does not produce full power.

The practice of VAZ 2109 owners shows that the most obvious sign of a breakdown of the engine is the engine stopping at idle while coasting, or the engine stopping when the clutch is pressed to change speed.

If the engine breaks down, the “Check Engine” light on the dashboard should light up. If the car is equipped with an on-board computer, then the error code corresponding to the malfunction is 24.

https://youtube.com/watch?v=qiDmZLUuTMI

Causes of failure

There are several main reasons why a DS may stop working:

1. There is a break in the electrical circuit. Therefore, first of all, we advise you to check the condition of the wiring and contacts. They could become dirty or oxidized. It's not difficult to clean them. Additionally, we recommend treating contacts with Litol.
2. Break near the connector. Here the wiring often bends and chafing occurs. Don't forget to check the condition of the insulation of the wires that are located near the exhaust manifold. Often they melt under the influence of temperature, which leads to short circuits.
3. The speedometer cable is worn out. Over time, as the vehicle is used, the cable becomes covered with burrs, cracks, and breaks. As a result, the speed sensor stops working properly.

https://youtube.com/watch?v=jsP9uC7EE-Q

Verification methods

The first thing you need to do is make sure that a voltage of 12 V is supplied to the DS contacts. Since the operation of the DS is based on the Hall effect, the test is performed by torsion. The voltage varies within 0.5-10V.

Today, there are three main ways to check the performance of a speed sensor. The first two involve the use of a multimeter. Which one to choose, decide for yourself. We will talk in detail about all three methods of checking DS.

If checking the DS shows that everything is fine with it, be sure to check the functionality of the sensor drive. It is necessary to hang up the front wheel and find the DS drive by touch. Now start rotating the wheel with your foot and check with your hand whether there is rotation in the drive and how stable it is. The help of a partner will not hurt you here.

Symptoms of malfunction

The main part of the speedometer is the speed sensor. Thanks to this unit, information is transmitted to the speedometer about how fast the car is moving on the road.

Symptoms of a malfunctioning speed sensor are:

1. Incorrect display of vehicle speed on the instrument panel. Or the speedometer does not show the car’s speed (the needle always remains at zero).
2. Engine instability at idle.
3. Increased vehicle fuel consumption.
4. The engine is not running at full power.

Work technology

Replacing the speedometer cable on a VAZ 21099 with a high and low instrument panel includes the following steps:

• the electrical system is de-energized, for which the battery is removed;
• then the instrument panel is dismantled;
• after ensuring access to the fastening elements, you need to unscrew the fastening nut and remove the slots from the device body;
• for ease of installation, the new cable is attached to the shell of the old one;
• the fastening nut of the drive installed on the gearbox is dismantled;
• the tip is removed from the spline connection;
• the old cable is pulled out of the engine compartment;
• after checking the correct position of the new cable, tighten the union nuts;
• the instrument panel is mounted in the reverse order;
• the battery is connected;
• The functionality of the device is checked.

It is important to consider some aspects when performing such work, for example:

• the cable should be lubricated using greases (Litol, CV joint, CIATIM);
• lubricant must also be applied to the spline joints;
• union nuts are mounted and dismantled using adjustable pliers;
• To prevent damage to the threads, screwing the nuts is done very smoothly, controlling the applied force.

Also, the cause of incorrect speed readings may be a failure of the gear drive. Its drive gear gradually wears down and loses connection with the gearbox. Therefore, before installing the speedometer cable, you should check the condition of this unit. When replacing this unit, you must ensure that the drive is applicable to this vehicle model.

The reason for the breakdown of the VAZ 2109 speedometer drive

Since the flexible shaft is the most basic part of the speedometer drive, a common cause of speedometer failure is its breakage. The shaft breaks due to normal wear and tear and must be replaced.

To check the operation of the shaft, the instrument panel is removed, the shell with the shaft is placed on the edge of the inner part of the torpedo, the engine is started and the vehicle is driven at a speed of 20 kilometers per hour. If the shaft does not rotate, then it is broken. If it rotates properly, then the problem lies in the speedometer mechanism itself.

Also, a drive malfunction may be due to wear of the gears, which are attached near the secondary shaft of the gearbox.

Pinout of the dashboard of VAZ2110, 2111, 2112

1. fuel reserve warning lamp;
2. dashboard lighting lamps;
3. right repeater indicator lamp;
4. left repeater indicator lamp;
5. VAZ plug block;
6. coolant temperature sensor;
7. indicator lamp for external lighting;
8. carburetor air damper warning lamp;
9. oil pressure warning lamp;
10. handbrake indicator lamp;
11. battery charge indicator lamp;
12. VAZ tachometer;
13. indicator light “CHECK ENGINE”;
14. speedometer dashboard;
15. brake fluid level warning lamp;
16. hazard warning lamp;
17. high beam indicator lamp;
18. fuel level indicator.