Priora speedometer does not work: 16 valves, why, reasons

The stable operation of injection power units depends on the synchronous functionality of all electronic components.

One of these important components is the electronic speedometer. The article will answer the question why the speedometer on a Lada Priora car does not work. Symptoms, causes of failure, and methods for checking damaged elements of the entire system will also be described.

Layout and operating principle

The Lada Priora model is equipped with a fully electronic speed calculation system. It consists of the following elements:

Speed sensor (EMF). Its function is to create electrical impulses.
Electrical wiring. Powers the speedometer system with electric current.
Fuse. Protects the system from voltage surges.
On-board computer. Monitors work and analyzes incoming data.
The speedometer itself. Necessary for visual speed control.

There are not many components in the system. The system works as follows:

The speed sensor produces electrical impulses. It is installed on the gearbox housing. On power units with 16 valves, the EMF is located on the side of the expansion tank. The EMF is installed opposite the flywheel. This gear has teeth along its entire diameter. There is only one tooth missing in one place. It is to this place that the magnetic speedometer sensor reacts. During the passage of an empty space, the EMF opens, thereby creating an electrical impulse.
The pulses generated by the opening are sent through wires to the ECU. The computer calculates the speed at which the signals arrive and converts them into an electrical voltage of a certain strength.
Voltage is supplied to the instrument panel, activating the speedometer drive motor.
The electric motor deflects the speedometer needle by a certain degree.

In addition to needle deflection, electrical impulses from the speed sensor are necessary to calculate the fuel supply to the engine. Based on the data received, the on-board computer determines the required amount of combustible mixture and its filling with air. In this way, the required, stable engine speed is maintained for the current speed limit.

The speedometer on the Priora does not work for several reasons. But this is always preceded by the appearance of a number of symptoms of a malfunction. They will be described below.

Malfunctions on VAZ

The speedometer on the VAZ stopped working.

Most domestic autospeedometers and odometers are mechanical. So, when a mechanical odometer fails, the main reason (almost always) is a broken cable.

This problem can be easily diagnosed by a characteristic noise in the front of the dashboard.

After breaking, the steel wires begin to touch the inside of the shell and “ring.” The main reason for the break is the large radius of curvature during cable installation.

A mechanical speedometer malfunction can manifest itself in different ways. For example, the needle on the device often lies as a “dead weight” or, conversely, shows deliberately false information.

In such a situation, you need to make sure that the speed sensor is working and that there is voltage on it. Also inspect the terminals for moisture penetration.

If there is voltage at the sensor, then the problem must be looked for in the device itself. In such a situation, it is easiest to replace it.

It happens that a sensor malfunction is associated with some kind of mechanical damage. In this case, you can try to disassemble the drive and fix the problem yourself.

If there is no voltage on the sensor, it is necessary to check all electrical connections on the way to the device - wires, blocks, terminals. It is likely that the contacts are broken or oxidized.

New cars have electronic speedometers and odometers, which receive data from the speed sensor at the gearbox.

Consequently, there can be two breakdowns - either in the odometer itself (in this case it is necessary to change the entire dashboard).

Or in the sensor (we talked about it above).

Symptoms

Drivers accustomed to carburetor engines often do not react to the appearance of symptoms of speedometer failure. On injection engines, you need to pay attention to the behavior of this device. Symptoms of failure are as follows:

The instrument needle does not work completely or partially. It can periodically turn on, tremble, freeze at a certain level.
Complete failure of the instrument panel.
The speedometer determines the speed limit with a large error.
The engine is losing power.
Fuel consumption increases noticeably.
The stability of the power unit at idle speed is lost.

All these signs are the result of a breakdown or malfunction of the components of the speed calculation system. A detailed analysis of the reasons will be given below.

Malfunctions on Priora

If the speedometer on a Priora stops working, the first thing you need to do is temporarily remove the terminals from the battery.

Did not help? – Then look for a fault in the device circuit. First, check the integrity of the instrument panel fuse.

If it burns out, replace it (but first make sure that all contact connections are intact).

If the problem persists or the fuse is normal, check all the wires on the path from the speed sensor to the instrument panel. This can be done using a multimeter.

If there are no complaints about the wiring, check the motion sensor with a special scanner. If there are malfunctions, the element must be replaced.

The serviceability of the motion sensor can be determined by the behavior of the odometer. If the speedometer does not work, but the odometer counts kilometers, then the sensor is working, and the breakdown must be looked for elsewhere.

For example, problems may be in the soldering on the dashboard circuit board or, even worse, in the gearbox. But this can only be found out at a service station with the help of a qualified technician.

As for the tachometer on the Priora, there are three causes of malfunctions:

violation of the tachometer supply circuit. In this case, you need to carefully crimp all the tips and replace damaged wires (if any);

violation of the functionality of the controller (the signal does not reach the tachometer). Only replacing the device will help here;

failure of the tachometer itself. This option is the most expensive, because it is not possible to change the device separately - you need to buy a new panel.

Malfunctions

If the speedometer on a Priora stops working, then you need to check each of its components step by step. It's better to start with the device itself.

Drive unit

The drive is checked by simply disconnecting the negative terminal of the battery. After reconnecting the terminal, the on-board computer reboots the system. Next, you need to reset the odometer, hold down the reset button and turn on the ignition. The tachometer and speedometer needles should deflect to the maximum. If this does not happen, then electrical voltage is not passing through these devices.

You can conduct an additional test of the speedometer's performance. On a Priora, the speedometer may not work due to a failure of the signal receiver drive. To check you need:

From the “+” terminal of the battery, run a wire to terminal “26” of the red connector.
With short touches you need to simulate the arrival of signals from the EMF.
The arrow should deflect each time terminal “26” is touched.

If there is no response to the incoming voltage, you will have to dismantle the panel and remove the instrument printed circuit board. It needs to be inspected for breaks or oxidation of soldering and tracks. The oxidation needs to be cleaned, and the broken tracks need to be soldered with jumpers. Next, perform the following test:

Set the tester to resistance measurement mode.
Connect the red measuring probe to terminal “26”.
Apply the black test lead to ground.
The pulse input should show an operating resistance of up to 3 ohms.

If these readings are not present, then the fault lies in the radio components of the drive or its motor has burned out. Without special knowledge, such breakdowns cannot be repaired on your own. You'll have to change the drive.

Fuse

The speedometer is protected by fuse “F1”. It is located in the safety block under the dashboard, on the driver's side. It is necessary to remove the element and check the condition of the internal jumper.

If it is broken, you need to replace the element with a 10 Ampere analogue. Before replacing, it is important to clean the fuse contacts from oxidation and possible carbon deposits.

After replacement, you need to check the operation of the speedometer again.

Wiring

It's just that fuses don't blow. This was preceded by a short circuit or high voltage.

It is necessary to carefully check the wiring for breaks, deformation, and lack of insulation. All defects found must be eliminated.

EMF

If the Priora's speedometer does not work, the cause may be the speed sensor. Its verification is carried out sequentially. First you need to check the condition of the connecting plug. It is necessary to open it and inspect the contacts of both parts of the socket. If dirt, moisture, or oxidation is detected, clean with a solvent. Next, you need to check whether the electrical voltage reaches the sensor itself. Necessary:

Set the multimeter to voltmeter mode to measure DC voltage.
Connect the red test probe to terminal “1” of the wiring cable.
Connect the black probe to terminal “3”.
Turn on the ignition.

The voltmeter should show a result equal to the battery voltage. If voltage is supplied, then the sensor’s ability to generate electrical impulses is checked. This test requires:

Raise the drive wheel of the vehicle on a jack.
Connect one end of the control wire to terminal “2” of the sensor.
Connect the red probe of the multimeter to the second end of the control wire.
Connect the black test lead to ground.
Insert the plug into the EMF socket.
Turn on the ignition.
Rotate the drive wheel of the machine.

As electrical voltage is applied to the sensor, it must produce electrical signals. The tester defines them as a pulse voltage from 0.6 to 12 volts. If there is no response from the tester, then you will have to dismantle the EMF to check.

To dismantle, you need to loosen the air purification filter pipe. The EMF is immediately visible directly below it. Its dismantling is carried out using the “10” key. You need to unscrew the mounting bolt and turn the sensor a little. Next, you need to pry the device with a screwdriver and remove it from its seat.

Since the EMF on the Priora is of a magnetic type, metal debris from the gearbox is often magnetized to its lower part of the body.

Metal particles prevent the magnet from opening, which makes it impossible to create an electrical impulse.

You need to thoroughly clean the device body and check its functionality. To do this, you need to connect the plug with the previously described wire connected to terminal “2”.

Connect the red probe of the multimeter to the wire.
Connect the black probe to ground.
Set the multimeter to DC voltage measurement mode.
Turn on the ignition.
Attach a screwdriver to the end of the sensor.
It should be magnetized.
The moment the screwdriver is disconnected from the sensor, a pulse should be created that will be visible on the multimeter display.

A more thorough test can be carried out by reinstalling the sensor and rotating the drive wheel. In this way, more accurate pulses can be obtained. You can conduct an additional test of the sensor by checking its electrical resistance.

This requires:

Set the multimeter to resistance measurement mode.
Connect the red probe of the tester to terminal “1”.
Black probe with terminal “3”.
Resistance should vary from 3 to 10 ohms.
Then you need to bring a metal object to the sensor.
The contacts should open and the readings on the multimeter should drop to “0”.

If the EMF does not pass the test, then it must be replaced with an exact analogue.

Speedometer does not work on Priora: reasons

If the speedometer on a Lada Priora car does not work, the first thing you should do is make sure that the problem is not related to bugs in the chip on which it operates. During operation, the chip's cache may become clogged with information, causing the speedometer to malfunction. To reset the speedometer chip settings, you need to reset the ground from the car battery and disconnect the power from the car's on-board network. Such simple manipulations will lead to resetting the settings of storage devices, including the speedometer chip.

When resetting the chip does not help to cope with the speedometer malfunction, you should conduct a full check of the power circuit. To do this you will need:

Check the fuse plate installed on the fuse board in the speedometer power supply circuit. The required fuse is designated "IG/METER";
Next, the serviceability of the wiring in the area from the speed registration sensor to the instrument panel is diagnosed. Often in this section the wires are torn, pinched and get other defects, largely due to the constant shaking of the car while driving on not the best roads;
Also, when checking the wiring, it is necessary to inspect the contacts in the connectors, which may become unusable due to oxidation and rust formation. It would be a good idea to clean the sensor contacts and connectors;
The next step is to check the vehicle distance control sensor. Service centers use diagnostic equipment to check it. If there are no diagnostic tools, you can check the operation of the sensor by driving a few kilometers. When the mileage count continues, this indicates that the sensor is working.

At this point, we can consider checking the speedometer power circuit complete.

If the problem cannot be detected, the problem may be related to the dashboard itself. To check this, you will need to remove the printed circuit board on which all the devices are located and carefully inspect it for damage, oxidation, melting, breaks and other defects. It is effective to check the board on a special diagnostic stand in a service center. When there are problems with the board, technicians can repair it.

Electronic failure options were discussed above, but we should also not forget that a possible reason for a non-working speedometer in a Priora is damage to the needle or its mechanisms. To verify this, you need to disassemble the device and inspect it for defects or their absence.

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