Lada Priora: EUR, faults and repair of electric amplifier

EUR - what is it?

Electric power steering is a kind of electric motor that helps the driver turn the steering wheel with less effort. The EUR is installed on the steering wheel shaft and, when the engine is running, helps to rotate the steering wheel, powered by electrical voltage.

The main task of the ESD in a car is to reduce the force of rotation of the steering wheel by the car driver.

What it consists of:

• Steering shaft;
• Torsion shaft;
• Electrical engine;
• EUR control unit;
• Motor rotor sensor;
• Torque sensor;
• Circuit breakers;

The components of the EUR include the following elements:

• Steering rack;
• Steering wheel;
• Speed ​​sensor;
• Steering cardans;

All these details directly affect the operation of the electric power steering of the Lada Priora.

We use the “folk” method of checking the malfunction

In the case when the light on the LADA Priora does not light up, and there are faults with the EUR, and perhaps it is necessary to carry out control after the repair work has been carried out, then you can do this: turn the car steering wheel, without the ignition on, remember the force. Next, start the engine and repeat the action. If there are no changes between the two actions, then it is obvious that the ESD is not in order, you need a more detailed diagnosis of the car, and then choose the most suitable methods for troubleshooting, and this, let us tell you, is not at all problematic.

Priora EUR control unit

This part serves to calculate the force applied to the steering wheel and the force that the electric motor applies to the steering wheel shaft. The block is also responsible for turning off the power steering at speeds above 100 km/h for a more sensitive understanding of the car.

The EUR control unit on the Lada Priora is located near the power steering electric motor on a special bracket.

Chip errors

When a situation is observed that the wheels turn on their own, the reason is the electronic filling of the Priora electric power steering control unit.
As mentioned above, quality was sacrificed for the sake of economy. Now the situation with this seems to have improved and everything has been finalized, but if suddenly you feel that the steering wheel is starting to move by itself, go for repairs. If, along with the electric power steering, the speedometer also fails, then you need to look at the speed sensor. It was either simply dirty or broken. The same applies to the torque sensor installed on the amplifier. Clean them well and check their functionality.

Don’t forget to reset errors on the on-board computer; this can be done in several ways.

1. Remove the terminal from the battery, wait a few seconds and put it back, the error should go away.
2. Using a computer, the corresponding software can be found on the Internet.

Differences between EUR and power steering

The electric amplifier differs from the hydraulic one in the absence of fluid and the pump necessary to pump this fluid. Also, the hydraulic power steering operates entirely on mechanics, unlike the electric power steering, in which mechanics are involved only in the rack and steering wheel. EUR is much simpler and easier to maintain, but in terms of repairs it is much more expensive.

Advantages and disadvantages of EUR over power steering

Although the EUR is more modern and technologically advanced, it has both advantages and disadvantages over the power steering.

Advantages:

• The simplest design that does not require constant monitoring of the liquid level (dixtron);
• There is no need to service the power steering pump, since it simply does not exist;
• Reduction of force with increasing vehicle speed;
• Ability to programmatically adjust steering wheel force;
• Reliability of the design;
• Compact, no bulky pump in the engine compartment and no extra hoses;
• The simplicity of the steering rack and its reliability, since it is dry and there is simply nothing to leak in it (everyone knows very well about the disease of “wet” racks);

Flaws:

• High power consumption, at some points the electric power steering can take up to 40% of the electrical power of the car’s generator and cause voltage drops in the on-board network;
• Possibility of overheating of the electric motor when driving on a dirt road (track) up to the complete shutdown of the power steering;

As you can see, the more modern power steering has many more advantages, which is why it is gaining great popularity among cars at the present time.

Let's sum it up

As you can see, the Priora EUR itself is not a complex design, which somewhat simplifies the process of replacing individual system components. However, the active use of electronics reduces the reliability of such a system as a whole. In practice, more often than not, malfunctions of the electric power steering occur not due to mechanical breakdowns, but as a result of problems with connectors, sensors, contacts, wiring, control modules, etc.

We also recommend reading the article on how to replace power steering fluid in a hydraulic booster with your own hands. From this article you will learn about the features of changing power steering oil, when to change power steering oil and how the replacement is performed.

In any case, with regard to ESD, it is necessary to start with computer diagnostics, and only then move on to an in-depth check of all system components individually.

Finally, we note that the problem with the electric booster cannot be ignored. Some owners try to reset ESD errors without identifying and eliminating the causes. In fact, you need to understand that the good condition and full functionality of the power steering is the key to a comfortable and safe ride.

For this reason, the power steering, regardless of type, must be periodically checked and serviced (in the case of power steering, you need to monitor the tightness and change the power steering oil; in the case of power steering, at least in-depth diagnostics should be performed). This approach makes it possible to increase the service life of the system and also avoid unexpected breakdowns of the vehicle's power steering.

Technical characteristics of the EUR

Design

Steering rack design: 1 – shaft boot, 2 – cover mounting bolts, 3 – Belleville washer, 4 – worm shaft oil seal, 5 – worm gear cover, 6 – sealing collar, 7 – thrust bearing, 8 – worm shaft with bearing, 9 – rasp, 10 – left boot, 11 – binoculars, 12 – binocular bracket, 13 – nut plug, 14 – thrust nut, 15 – thrust spring, 16 – locking collar, 17 – thrust piston collar, 18 – thrust rasp piston, 19 – piston liner, 20 – steering rod bolt, 21 – stopper, 22 – plate, 23 – plastic clamp, 24 – steering rack boot, 25 – left side boot, 26 – steering rack pipe.

Removal and installation

To carry out work on removing and installing the electric power steering on a Priora, you need to prepare a special tool that will be needed during the work process.

You will need:

• Hammer;
• Wedge (a chisel will do);
• Ratchet;
• Ratchet extension;
• Head for “8” and “13” mm;

After preparing the tool, you can begin to work.

Removal

• Disable the mass mark from the battery;
• dismantle the steering column casing;
• Remove the ignition switch by unscrewing the bolts;
• Remove all connectors from the power steering unit;
• We unscrew the steering cardan nut and use a wedge to loosen its engagement on the splines;
• Unscrew the nuts securing the amplifier to the body (4 pcs);
• We remove the structure from the car;
• We assemble in the reverse order;

Device

The main components of the EUR are:

• electrical part;
• mechanical;
• controller and peripherals.

The first category includes, in particular, the electric motor.

The mechanical part consists of:

• steering wheel parts;
• connections;
• input and output shafts;
• bracket;
• tilt adjustment lever;
• studs, bolts, nuts, etc.

This also includes the steering rack.

As practice has shown, most often it is electronic devices that fail, that is, ECUs, sensors and the distribution terminals connecting them.

Battery problems

Based on this, we can draw the first conclusions about the cause of the breakdown. A common cause of malfunction is low voltage in the on-board network. The fact is that for the amplifier to function, a supply voltage of 13.5V is required.

First of all, we test the battery, if everything is fine with it, then we’ll look into it further. The problem may have occurred when you removed the battery for charging. To make the electric booster work again, turn the wheels to the extreme position and back 5-6 times, very often this is enough to resume operation.

Prevention measures

To maximize the service life of the Priora steering rack, follow simple operating rules:

• bumps, potholes and speed bumps must be driven over at low speed and carefully;
• periodically inspect the condition of the anthers and seals;
• The oil in the power steering should be warmed up before driving (short turns by steering wheel);
• It is not recommended to frequently hold the steering wheel in the extreme right or left position.

By following these simple rules, you can avoid expensive repairs or replacement of the unit.

Unpredictable operation of the electric amplifier

It is much more dangerous when the electric amplifier behaves unpredictably. For some car owners, while driving, the amplifier began to work and sharply turn the car to the side, while the driver was driving on a flat road and did not affect the steering wheel. Such situations may be accompanied by jolts to the steering wheel. It turns out that at the most inopportune moment, the electric power steering can knock the steering wheel out of your hands and send the car either into the oncoming lane or to the side of the road.

Steering wheel and dashboard

If such a malfunction occurs, it is absolutely prohibited to continue driving, otherwise, due to this breakdown, you can get into a traffic accident or fly off the road. To continue further movement, just turn off the amplifier. To do this, you need to remove the fuse responsible for power supply to the electric power steering, after which you can continue driving without the amplifier.

The origin of this problem lies in the amplifier itself. Such a malfunction may occur due to the same torque sensor. If the contact group is dirty, this sensor may not correctly perceive the steering position and speed sensor data. In some cases, cleaning the contact group can restore the functionality of the amplifier. But it is quite possible that such an operation will not bring a positive result.

To eliminate the breakdown, most likely, you will have to completely replace the electric amplifier. It is not recommended to carry out replacement in a garage environment. To do this, it is better to contact a specialized service station. After replacing the electric booster, it is advisable to perform adjustment work on all components of the steering mechanism.

Design

Steering rack design: 1 – shaft boot, 2 – cover mounting bolts, 3 – Belleville washer, 4 – worm shaft oil seal, 5 – worm gear cover, 6 – sealing collar, 7 – thrust bearing, 8 – worm shaft with bearing, 9 – rasp, 10 – left boot, 11 – binoculars, 12 – binocular bracket, 13 – nut plug, 14 – thrust nut, 15 – thrust spring, 16 – locking collar, 17 – thrust piston collar, 18 – thrust rasp piston, 19 – piston liner, 20 – steering rod bolt, 21 – stopper, 22 – plate, 23 – plastic clamp, 24 – steering rack boot, 25 – left side boot, 26 – steering rack pipe.

Electric booster repair on a Priora: faults and their symptoms

Undoubtedly, the electric booster is a more reliable unit than a device running on hydraulics, but malfunctions also appear in the power steering. If they are detected, repairs must be carried out immediately, since the safety of the driver, his companions and other road users depends on the operation of the amplifier.

Complete failure of the EUR

As practice shows, this unit does not have many faults; breakdowns occur in the same parts. The first thing worth considering is the complete failure of the ESD. When you turn off the amplifier, you need to check the on-board computer screen; most likely, you will see a code there indicating a malfunction in the unit. But sometimes it is possible to determine when an amplifier is turned off only in practice.

We perform the following actions:

1. Turn off the engine and turn the steering wheel in different directions several times;
2. We repeat these steps, but with the engine running;
3. Has the steering effort changed? This means the node has completely shut down.

Even with the ESD not working, you can continue driving, but this is not recommended. The driver needs time to get used to driving with the help of an amplifier. It is better to immediately begin diagnostics and determine which component requires repair or replacement.

It is necessary to check for damage or breaks in the wiring.
Sometimes the amplifier and speedometer stop working at the same time. The cause of this defect is a speed sensor that has failed. Taking a look at the electrical diagram, you will understand that these three elements are connected. The torque sensor supplies data to the control unit, it compares it with speed and determines the force. If the cause is the speed sensor, then the repair consists of checking the wiring that leads to this element. It is also worth checking the wires connecting the sensor to the speedometer and power steering. If there are no breaks in the switching, then the sensor should be changed.

Low voltage in the car network can also lead to the ESD turning off. Faults should be looked for in the wiring insulation. If it is damaged, short circuits will appear in the network. Also, violations in insulation lead to malfunction of the generator. To troubleshoot the problem, check the wiring and generator. The torque sensor contains many contacts, which, if heavily soiled, help turn off the power steering. In this case, repair means disassembling the unit and cleaning the contacts of the torque sensor.

Unpredictable steering behavior

The driver is driving on a flat road, the position of the steering wheel does not change, and suddenly the car turns to the side. Such unpredictable behavior of the power steering requires urgent diagnosis, since at the most inopportune moment the electric power steering of the Lada Priora can send the car to the side of the road or into the oncoming lane. In such a situation, you should stop driving and turn off the amplifier. To do this, we need to remove the fuse, which is responsible for supplying voltage to the amplifier.

To remove this fuse, you need to do the following:

1. The mounting block cover is located at the driver’s left foot;
2. We turn the clamps and unclip the fasteners;
3. You will find the block where the required fuse is located near the expansion tank;
4. Feel free to take out fuse F5 (50 A) - it is responsible for providing the power supply circuit to the power steering unit.

You need to get the F5 50A to turn off the electric booster.
The reason for this behavior is a malfunction in the electric booster device. This could be a torque sensor, control unit, clogged contacts or mechanical damage. It is recommended that diagnostics be carried out by professionals, since in a garage you will not be able to check the control unit; replacement can be done with your own hands.