Some motorists flinch nervously when the ABS light comes on. They believe that in this case something bad happened to the braking system as a whole. The entire Internet is being shoveled in search of explanations for the current unpleasant situation. Why did the ABS light come on and what should be done in this case? But panic is inappropriate in this case and is hardly justified. The brake system of the car must be in good condition, only the anti-lock braking system will turn out to be inoperative, which is not at all so critical. Of course, it helps out in some critical situations, but this is all fixable and we will talk about it in more detail in our article.
Reasons for the ABS light to come on
We list the main reasons suggesting a constantly burning ABS light on the dashboard:
- lost contact in the plug-in connector;
Lost connection with one of the sensors, possibly due to a wire break;
The anti-lock braking system sensor is out of order, it should be checked with subsequent replacement;
The crown on the hub has fallen into disrepair;
Faulty ABS control unit.
After you have carried out the inspection, and the cause, at first glance, has been eliminated, check the operation of the anti-lock braking system. This is very simple to do, just accelerate the car to 40 km / h and brake sharply. vibrates and the flashing light turns off.
If a visual inspection of damage in the sensor circuit to the block did not give any results, then computer diagnostics will be needed to determine the specific error code for the anti-lock brake system. On vehicles with an on-board computer installed, this task is greatly simplified. It will only be necessary to correctly decipher the displayed code and determine the location of the problem.
How to independently check the malfunctions of the ABS light bulb?
We note the fact that the anti-lock braking system functions normally only if the ABS light comes on when the ignition is turned on and goes out after a few seconds. First of all, if the ABS light stays on, check the anti-lock brake fuse and inspect the wheel sensors. It often happens that the sensor connector on the hub is oxidized or the wires are frayed, and if the icon stays on after replacing the hub or pads, then the first logical thought that comes to mind is that the sensor connector is not connected. If the sensor is stuck with dirt, then this can also contribute to the light bulb.
Quite often, the appearance of an orange ABS indicator after a good slip can cause panic in motorists. But you don't have to worry at all in this case. Brake hard a few times and everything will be back to normal. This is a completely normal reaction of the control unit to this state of affairs. If the ABS light flashes periodically, then you should carefully examine all the contacts, and most likely you will find the reason for this behavior of the indicator and easily eliminate it.
Fixing the ABS light on
As mentioned earlier, do not panic. Let's see what can be done to fix the problem, without contacting a car service.
1. Open the hood and disconnect the battery.
2. The ABS electronic control unit is easy to find, it is located under the hood, often in the same housing with a hydraulic modulator - an element that distributes braking forces. You will recognize it by the multiple brake pipes that run to the block, as well as a bunch of wires with a connector.
3. Disconnect this connector and carefully inspect it for damage or moisture. Blow out the connector as needed and dry.
4. Check the fuses, which most likely should have been done first. But don't be afraid.
5. If there is a car lift available, then look at it. If not, then use a jack and raise the car. Your task is to inspect the wires going to the wheel sensors for damage. These wires often fly off the mounts and fray against the wheel.
6.
Wheel sensors are built in such a way that a wire with a connector at the end extends from them. It can reach one meter. Your task is to find these connectors and check the presence of a contact and its quality. Make sure that there is no moisture and rust.
7. If everything is normal, but the ABS light continues to burn, then definitely go to a car service. An error in the anti-lock braking system of the brakes is not always eliminated by a “reboot” by removing the battery terminal.
Everything described here refers to self-search and troubleshooting. In a specialized automotive service, a scanner will be connected to your car, which will determine the breakdown.
Some motorists are afraid that when the ABS is on, it somehow affects the operation of the braking system as a whole. They urgently begin to search the entire Internet in search of an answer to why the ABS light is on and what to do. But do not panic like that, the brakes on your car should be in perfect order, only the anti-lock system will not work, which, in principle, is not critical, although it helps out a lot in some emergency situations. And in order to deal with the system, I recommend reading about.
What to do if the ABS light is on?
It is worth noting that the system works normally if the ABS icon lights up when the ignition is turned on and goes out after a couple of seconds. First, What to do if the ABS light stays on is to check the fuse of this system, as well as inspect the wheel sensors.
Quite often, either the sensor connector on the hub is oxidized or the wires are frayed. And if the ABS icon is on after replacing the pads or hub, then the first logical thought is - forgot to connect the sensor connector. The presence of dirt on the sensor also contributes to the light of the indicator.
Quite often, car owners can be frightened by the appearance of an orange ABS icon after a good slip. In this case, you should not bother at all: brake sharply a couple of times and everything will pass by itself - the normal reaction of the control unit to such a situation. When ABS light stays on intermittently, and periodically, then you need to inspect all the contacts, and most likely, the cause of the signal indicator lighting up can be quickly found and eliminated.
Causes of the ABS error
The main possible causes of a constant on the dashboard:
- lost contact in the connection connector;
- loss of communication with one of the sensors (possibly a wire break);
- the ABS sensor is out of order (the sensor needs to be checked with subsequent replacement);
- the crown on the hub is damaged;
- failure of the ABS control unit.
After inspection and, it would seem, eliminating the cause, it is very easy, you just need to accelerate to 40 km and brake sharply - the vibration of the pedal will make itself felt, and the icon will go out.
If a simple inspection for damage in the sensor circuit to the block did not find anything, then diagnostics will be needed to identify specific error code anti-lock brake systems. On cars where an on-board computer is installed, this task is simplified, it is only necessary to clearly understand the decoding of the code, and where a problem could arise.
Vesta, Largus, Granta, Kalina, Priora, Niva 4×4) without exception are equipped with ABS (anti-lock braking system).
During the operation of the car, many owners notice that the ABS and ESC lamps (if this system is available) light up on the instrument panel. We figure out how to solve this problem and finalize the design.
WHY THE ABS AND ESC LADA IS ON
An ABS malfunction can be caused by:
- failure of wheel rotation sensors;
- malfunction of the hydraulic valve block;
- wiring damage.
If the ABS malfunction indicator lamp lights up, you should contact a service station as soon as possible for diagnostics (read error codes) and repair.
The most common cause of ABS failure is damage to the wiring near the ABS sensor connector. It is under the fender liner, but still not well enough protected from moisture and dirt.
As a result, the wires oxidize and break, the ABS lamp lights up.
HOW TO REPAIR LADA WIRING
We remove the wheel, and then the locker (for the front wheel, unscrewing the fastening screws) or the protective shield (for the rear, unscrewing the two fastening nuts “by 10”). We press the latch and disconnect the block with wires from the ABS sensor. We inspect the connector and make sure there is no corrosion or damage. In case of damage, we restore the integrity of the wires:
We treat with a special agent for cleaning electrical contacts (for example, graphite grease) and clean the contacts from oxides. We clean the wheel speed sensor and the surface around the sensor from dirt.
Attention! Keep the ABS sensors away from the magnets as this may damage them.
Articles about Lada X Ray Cross
REPLACEMENT OF ABS SENSORS LADA
If the cause of the malfunction is not in the wiring, but in the ABS sensor itself, we change it. To do this, first unscrew the fastening screw with a Torx T30 key, and then remove the sensor wiring harness from the bracket. The photo shows a Lada Vesta car, on other Lada models the work is done in a similar way.
Instructions for replacing the front wheel ABS sensor: 
Instructions for replacing the rear wheel ABS sensor: 
HOW TO MODIFY THE LADA DESIGN
To protect the wiring harness from the environment, you can use a D-shaped seal. We put the wires in it and wrap it with electrical tape. We put everything in the corrugation. We glue the cover covering the ABS sensor connector around the perimeter with the same sealant. This will prevent moisture and dirt from entering the sensor and connector area. 
Attention! If the ABS fails, the brakes remain functional, but the braking efficiency decreases, which is especially dangerous on how much coverage.
Novice drivers are often frightened by the various lights that suddenly light up on the dashboard of modern cars. If ABS, then you should not panic. The problem is not the most serious, it does not require large financial investments to fix it.
How is the ABS light supposed to work?
Consists of several functional blocks. This will make it easier and faster to understand the problem, due to which the indicator lights up.
The system consists of rotation sensors - there can be two, three or four of them. The system also includes an electronic module or control unit. In addition, the device has a self-diagnosis module and a light indicator on the dashboard.
If immediately after the start or during the movement, then this indicates that the anti-lock braking system is disabled. Many drivers mistakenly think that when the light is on, there are any problems with the operation of the brake system. This is wrong. The brake system has a separate diagnostic module and indicator. But this applies only to modern cars in a good configuration.
In the first few seconds after starting the engine, all the lamps and indicators that are on the instrument panel are lit. If the ABS indicator does not light up at startup, then there is some kind of malfunction in the system.
ABS?
Based on how the anti-lock braking system is arranged, it can be easily concluded that the lamp can burn for the following reasons:
- This may be a malfunction of the ABS sensors installed near the wheels, damage to the electronic unit, wiring. Problems with the crowns on the wheel hubs are not ruled out. Often, chassis parts can move or change their position, as a result of which the position of the sensors is disturbed. It can also be caused by a blown fuse.
- On some models from VAG, which were produced in the late nineties, there is one feature that is associated with the inclusion of an ABS error signal, and the malfunction itself is located in another node.
All of the above can lead to the fact that the ABS light comes on when the car is moving. For example, vibrations caused by rough roads very often lead to a break in the wiring. In the process of driving on bad roads or where they are absent at all, the sensors can become covered with mud, sand.
This will prevent them from transmitting the correct information to the electronic unit and will cause the light to turn on.
Self-diagnosis
Car diagnostic specialists recommend initially looking for a malfunction yourself. The first step is to visit a car wash and thoroughly clean the rims and hubs, as well as the places where the ABS sensors are installed. Quite often, after washing, the system starts to work properly. If after that nothing happened, then you should proceed to a detailed diagnosis.
In order to find out why an anti-lock braking system alarm occurs, you can use a very simple test. The vehicle is accelerated to a speed of approximately 100 kilometers per hour, then the radio is turned off and the windows are closed. If a characteristic noise is heard coming from the area of \u200b\u200bthe front or rear wheels, then the hubs or bearings need to be replaced.
Additionally, you can check other nodes. Check the fuse box and if there are bad fuses associated with the anti-lock system, they are changed. If possible, if the ABS light is on, they try to determine the error code - it can quickly identify the element that causes the problem.
It is also worth consulting with an experienced mechanic, describing to him the situation and the essence of the problem. Then you can try with your own hands to restore the correct operation of the anti-lock braking system.
Next, check the sensors. You may need to jack up the car and remove the wheels to access them. It will not be superfluous to conduct a complete inspection and tests of the electronic control system of nodes in the car.
Service stations
If all else fails and the ABS light is still on on the panel, you need to use the services of masters from specialized service centers.
This will cost you much more than in the case of self-diagnosis and repair. However, sometimes this is the only right way. Experienced craftsmen will help you find the source of problems, determine further tactics and the budget for future repairs. Competent diagnosticians will perform tests and detect errors in the operation of the anti-lock braking system, if any.
So, in a short period of time, with the help of scanners and specialized devices, you can collect all the important information about the state of the main components of the vehicle, find errors that will help you determine the breakdown as accurately as possible.
ABS indicator blinking
When the ABS light comes on, this may indicate a malfunction, and this is understandable, but if the indicator blinks, then the situation is much more complicated. The whole problem is that the sensors react incorrectly to the situation - they incorrectly read and transmit incorrect information to the main unit. After this malfunction, most motorists decide to completely turn off the ABS, as this is an effective measure to prevent serious consequences when driving. So, if the ABS light comes on after accelerating and the system is activated while driving, this can lead to very serious damage.
What to do if the indicator blinks?
In this case, we can only recommend diagnostics in a car service. If the anti-lock braking system is on a domestic car, then it is much easier and cheaper to turn it off, and not engage in expensive ABS repairs. It is possible that after it you will need to flash the ECU, but this is only relevant for foreign cars.
Conclusion
So, we examined why the anti-lock braking system lamp is on. It must be remembered that disabling the system is not the best solution to the problem, since on most car models ABS is simply necessary, its presence is due to the design features of the body and chassis.
If the ABS light on the instrument panel lights up, this indicates a malfunction in the car's anti-lock braking system. In most cases, this icon lights up simultaneously with the icons of other related systems: ESP, ASR (exchange stability, traction control, etc.)
The ABS error indication shows the complete inoperability of the system, and not the error of its individual elements, as in the case of an error in the engine management system. In the ABS system, as a rule, there are no emergency modes of operation. Failure of one of the devices leads to a complete failure of the entire system.
This is especially dangerous when the vehicle is operating on poor road surfaces. It is necessary to make computer diagnostics in order to find out why the ABS light is on - to determine all possible causes of the malfunction, to take measures to eliminate them.
The main causes of a malfunction of the ABS system
In general terms, a typical car ABS system looks like.
Usually, the ABS electronic control unit and the modulator (valve-controlled pump) are combined into a single unit. The principle of operation of the system is to briefly block the supply of pressure to the brake tube of the wheel, if the corresponding sensor showed no wheel rotation.
Experienced drivers know that on vehicles without ABS, it is necessary to brake on slippery roads by briefly depressing the brake pedal to prevent the wheel from locking. If the wheels lock up, the car becomes uncontrollable, which can lead to an accident.
The main causes of ABS system failure are:
- malfunction of the electronic control unit;
- failure of solenoid valves in the modulator;
- malfunction of wheel rotation sensors;
- damage to the wiring to the wheel rotation sensors;
- damage or clogging of the rotation sensor zone (in the figure shown - the ring gear);
- failure of the fuses for the power supply of the ABS unit, especially the one serving the pump in the modulator;
- loss of communication on the CAN bus.
The ABS unit can receive and transmit information to other systems: engine control unit, indicator panel, body control unit. The processing of information from the traction control system and the stability control system is also carried out by the ABS control unit.
Troubleshooting
The most reliable way to determine a faulty device, node or sensor is computer diagnostics.
Some cars before the year 2000 allow diagnosing the system using blink codes (closing certain contacts on the diagnostic connector, determining the error code by blinking the signal light). In Chrysler Group vehicles, error codes can be determined after turning the ignition on and off three times. They will be displayed on the digital odometer.
Video - what to do if the ABS light on the dashboard of the Toyota Carina E lights up:
After reading the error code, it is necessary to decrypt it, if the diagnostic scanner software does not do this automatically. Next, you need to start troubleshooting.
What to do in various situations if the ABS light on the instrument panel is on
1. The error code indicates a failure (open circuit or short circuit) of the speed sensor of a certain wheel (for example, rear right)
Such malfunctions are the most likely in the ABS system. Do not immediately buy a new sensor. In most cases, the malfunction is due to damage to the wiring connecting the sensors to the ABS control unit. The best option for determining the location of a break is a "continuity" (measurement of resistance in the circuit), starting from the connector of the ABS control unit. To do this, you need to know the electrical circuit for a particular unit.
For Mercedes Sprinter 2005 MY the ABS block connection diagram looks like.
It shows that the wheel sensors are connected to pins 12-13, 16-15, 14-29 and 31-30. In order to ring the sensors from the connector, you must disconnect the ABS block connector and find the appropriate contacts. Connector pinout for Mercedes Sprinter (2005 onwards)
If there is no connector pinout, you can find the numbers of the extreme contacts on the connector itself, it is usually printed on it.
The sensor and wiring are considered to be working if the multimeter readings are less than 1000 ohms in at least one direction, but not less than 10 ohms (wiring short circuit). If the resistance value is infinite in both directions, there is an open in the circuit or sensor.
You need to check the resistance at the sensor connector. They are either near the front wheel post or in the rear row of seats for the rear wheel speed sensors. If the sensor does not ring, it should be changed.
Video - why the ABS is on on the instrument panel of Priora, Kalina, Grant (fault diagnosis):
If the sensor is ringing, but the wiring as a whole is not, you should look for a break in the wiring connecting the sensor to the ABS control unit. Sometimes there are up to 3 cases of a break, especially if the car has been operated for a long time with a faulty ABS system.
2. The error code indicates the absence of a signal from a certain wheel speed sensor
At certified service stations, there are special devices that record the shape of electrical signals - oscilloscopes. The type of electrical signals from the speed sensor should be approximately the same.
The pulse frequency depends on the speed of rotation of the wheel, the amplitude (range) - on the sensitivity of the sensor. If the teeth on the wheel axle, from which information is read by the sensor, are clogged, the amplitude is greatly reduced. The ABS unit may not see this information.
In some car models, information about the rotation of the wheel is transmitted by a special rubber or plastic ring with magnetic segments. Very often, when repairing a hub, car mechanics do not even think about why it is necessary, and simply do not install it or remove it deliberately, as an extra element.
Sometimes a pebble gets into the gap between the teeth and the sensor, which pushes the sensor away, reducing its sensitivity. In such situations, it is necessary to clean the gap and adjust it.
3. Failure of the electrovalves of the pressure regulator
The malfunction is considered critical, usually requires aggregate repair (replacement with a serviceable ABS unit or a new one). Repair of the modulator is extremely difficult.
4. Fault in power circuits
In such a situation, the ABS unit may not be diagnosed at all, or the pump. It is necessary to check all the fuses responsible for servicing the ABS system.
5. No communication via CAN bus
This is a kind of local network that connects all vehicle control units to automate control, monitoring and indication. The malfunction is one of the complex ones, the intervention of a specialist is required. The CAN bus represents the twisting of conductors.
If an open or short circuit occurs somewhere in the circuit, the control units, including the ABS, lose contact with each other, information about the vehicle speed from the engine control unit may not be transmitted to the ABS, it enters emergency mode.
The ABS system refers to the braking system of the engine, traffic safety depends on its proper operation. You should not save on its repair and maintenance.
When contacting a service station regarding the repair of ABS, ESP, ASR systems, ask if the workshop is certified for this type of repair. Reputable service stations that repair and service brake systems should have a stand similar to when passing inspection. Simple services of an auto electrician to eliminate errors may not be enough for the correct operation of the ABS.
Do not pay for work immediately after the elimination (especially simple removal) of errors. Be sure to require bench and sea trials. In many cases, even after a quality repair, the error reappears after several braking and turning.
