The ABS system is installed on many modern cars. Toyota Corolla 2007, 2008, and cars of more recent years of production were also equipped with this system. However, often motorists are faced with the following problem: the ABS sensor lights up. This means that you need to check the ABS or the sensor itself.
How is ABS used?
The ABC system is necessary to stabilize braking and improve the behavior of the wheels on difficult sections of the road: for example, it should work when braking hard on a slippery road, when skidding. The task of the ABS unit is to prevent the brakes from locking up and the body of the car from skidding: in this way, the driver will be able to maintain controllability. It will be possible to press the brake pedal all the way down without thinking about the intermittency of this action, which the car will perform itself.
During emergency braking, slippage will not occur, which is why it is important to ensure that the anti-lock block is in good working order.
How does the anti-lock brake system work?
In order to understand whether the system works correctly, you need to know how it should work in good condition. On the Toyota Corolla 120, the system works as follows: as soon as braking begins, sensors installed on the wheels of the car monitor the initial braking impulse.
The control of the hydraulic cylinders takes place via an electrical wire, this helps to prevent slippage, as the sensor sends a signal to the system that the brake may be blocked. Thanks to this, there is a strong grip on the road and skidding does not occur.
On vehicles without a sensor, the driver must control the situation by removing his foot from the brake pedal and pressing it again, however, it is quite difficult to accurately track the moment when the car lost traction, and skidding becomes inevitable.
Why might errors occur?
The Corolla 150 is a reliable car, but Russian operating conditions may not affect the sensors in the best way. Most often, if the ABS icon appears on the dashboard, you need to check for malfunctions of the ABS sensor.
When the engine is turned on, the light should light up and go out after a certain time: this is a normal reaction of the system to turn on, however, if the ABS lamp turns off again, this indicates a malfunction in the control unit or sensor. The notification may light up for the following reasons: the fuses are out of order, the wires of the electrical system do not pass pulses well, the sensor itself is faulty, the control unit has failed, communication with the sensor has been lost.
If the lamp does not burn constantly, blinks frequently, then the problem may be in the operation of the car's generator.
How to check for a problem?
It is best to check the operation of Toyota Corolla ABS in a specialized car service, where they can determine exactly what the problem is and fix it. If the car has an on-board computer, the master will be able to read the error number and understand what's wrong.
However, some manipulations can be carried out independently.
Without this element, the device will not work. You can find the fuse block under the hood: check the fuses, connectors, replace blown ones if necessary.
The control unit is also under the hood. You can find the control unit by the tubes coming from the brakes and wires. The control unit may receive mechanical damage, so you must first inspect it visually. First, the electrical wire will need to be removed from it. Check if water has entered the unit: if it is wet, it needs to be dried.
After washing, a similar problem can also occur, as moisture gets on the wiring. A wet wire shorts out and the wheel sensor cannot communicate with other parts of the system; in this situation, you need to wait until the wire dries.
Serious repairs may be required if the hub bearing is defective. To do this, you need to accelerate the car to at least 80 km / h and listen: if a distinct hum is heard, then the bearing needs to be replaced. Most often, the front one breaks, but if, for example, the rear left requires repair, the bearings are replaced on both sides of the axle. If the rear bearing fails, it is not necessary to change the front right or left element.
In the same situation, you can check the brakes. Pay attention to how the car behaves when you press the pedal, whether it skids, whether the impact on it is noticeable from the working ABS. You will quickly understand if the system is not working. If the ABS sensor does not work, you will need to raise the car on a lift: each wheel has its own sensor, so you need to check them one by one. The connectors may oxidize, the sensors themselves may become clogged with dirt. You also need to check the integrity of the wires.
Conclusion
It is possible to use the car while the ABS light is on, but it is better to have the vehicle repaired, as the wheels may lose traction on slippery surfaces, which will affect your safety. Serious repairs are recommended to be done in the workshop, but you can determine what the problem is on your own, for which you can use a minimum of tools.
Toyota Corolla is equipped with a set of security systems designed to reduce the likelihood of an emergency, and in the event of a traffic accident - maximum protection for the driver and passengers.
ABS - anti-lock braking system. Prevents wheel lock during emergency braking or when braking on slippery roads.
EBD - brake force distribution system. It is part of the anti-lock braking system.
TRC - traction control. If slippage of the drive wheels occurs during acceleration, the system automatically reduces the engine torque and brakes the wheel that has fallen into slippage, helping to restore traction.
VSC - system of exchange rate stability. Automatically triggered after it detects a skid due to hard steering or lack of contact with a slippery road. By braking one or another wheel and changing the engine torque, it brings the car out of a skid and helps the driver to stabilize the trajectory of movement.
BA - emergency braking assistance system. Provides emergency braking in the event that the driver presses the brake pedal sharply, but not hard enough. To do this, the system measures how quickly and with what force the pedal is pressed, after which, if necessary, it instantly increases the pressure in the brake system to the maximum effective one.
ABS Toyota Corolla
The anti-lock braking system (ABS) consists of wheel speed sensors, a brake pedal switch, a hydro-electronic control module and signaling devices in the instrument cluster. The anti-lock braking system includes an brake force distribution (EBD) system and a self-diagnostic system that detects malfunctions of system components.
ABS serves to regulate the pressure in the brake mechanisms of all wheels when braking in difficult road conditions and thereby prevents the wheels from locking.
The ABS system provides the following benefits:
Detour of obstacles with a higher degree of safety, including during emergency braking;
Reducing the braking distance during emergency braking while maintaining roadholding and controllability of the car, 8 including in a turn.
In the event of a system failure, functions for diagnosing and maintaining operation in case of system failures are provided.
The hydro-electronic control module receives information about vehicle speed, direction of travel and road conditions from the wheel speed sensors and the throttle position sensor. After the ignition is switched on, the control unit supplies voltage to the wheel speed sensors. They use the Hall effect, they generate an output signal in the form of pulses. The signal changes in proportion to the rotational speed of the encoder's pulse ring.
Based on this information, the control unit determines the optimal wheel braking mode.
There are the following modes of operation of the anti-lock braking system:
Normal braking mode. During normal braking, the intake valve is open and the exhaust valve is closed. When the brake pedal is pressed, brake fluid is supplied under pressure to the working cylinder and actuates the brake mechanisms of the wheels. When the brake pedal is released, the brake fluid returns to the brake master cylinder through the intake and check valves;
Emergency braking mode. If a wheel lock occurs during emergency braking, the module issues a command to the pump motor to reduce the supply of brake fluid, then voltage is applied to each solenoid valve. The intake valve closes and the brake fluid supply from the master cylinder and pump is shut off; the inlet valve opens, and the brake fluid flows from the working cylinder to the master cylinder, and then to the reservoir, which causes a decrease in pressure;
Pressure maintenance mode. When the pressure in the working cylinder is reduced to the maximum, the module issues a command to maintain the brake fluid pressure, voltage is applied to the intake valve and not applied to the exhaust valve. At the same time, the inlet and outlet valves are closed and the brake fluid does not leave the working cylinder;
Pressurization mode. If the module determines that the wheel is not blocked, then the voltage is not applied to the solenoid valves, the brake fluid through the inlet valve enters the working cylinder, the pressure in which increases.
Diagnosing and repairing the anti-lock braking system requires special equipment and equipment, so if it fails, contact a specialized service station.
If the anti-lock brake system warning light comes on in the instrument cluster, the diagnostic code can determine the cause of the system malfunction. To check for trouble codes, do the following.
1. Pry up the latch...
3. Establish between contacts of a diagnostic socket "4" and "13" a control lamp for reading of codes of malfunction of antiblocking system of brakes.
4. Set the ignition key (lock) to the "ON" position.
5. After 4 s, the control lamp will flash, for example: flash, pause (approx. 1.5 s), flash, flash, flash (standard at 4 s intervals). Counting the number of flashes before and after the pause, we determine the fault code
If there are two or more faults in the system, a series of flashes are repeated in blocks in which fault codes are displayed sequentially at intervals of 2.5 seconds, and blocks are repeated at an interval of 4 seconds. If the control lamp does not light up, check the connections of output "4" with "ground" and output "13" with the control unit.
If there are no faults, the control lamp flashes at intervals of 0.25 s.
6. Set the ignition key to the "ACC" position and disconnect the control lamp from the diagnostic socket.
7. Set the steering wheel to the straight ahead position.
8. Establish between contacts "4" and "12" of a diagnostic socket a control lamp for reading of codes of malfunction of antiblocking system of brakes.
9. Turn the ignition key to the "ON" position. The control lamp should first light up for a few seconds and then start flashing. If the control lamp does not light up, check the connections of output "4" with "ground" and output "12" with the control unit.
10. Drive the vehicle for a test drive in a straight line at a speed of at least 45 km/h and no more than 80 km/h. While driving, the indicator lamp should go out.
11. Stop the car - the control lamp should flash.
12. Install an additional control lamp between contacts "4" and "13" of the diagnostic connector and perform the operations of step 5.
13. To exit the mode of checking the ABS fault codes, turn off the ignition and remove the control lamps.
To eliminate fault codes from the memory of the control unit, do the following.
1. Pry up the latch.
2. ... and open the cover of the diagnostic connector.
3. Establish between contacts "4" and "13" of a diagnostic socket a control lamp for reading of codes of malfunction of antiblocking system of brakes.
4. Set the ignition key (lock) to the "ON" position.
5. Press the brake pedal at least 8 times within 5 seconds.
6. The control lamp should show no malfunctions, i.e. flash at 0.25 s intervals. Otherwise, repeat the operations in paragraphs. 4 and 5.
7. Switch off ignition and remove a control lamp.
REPLACING WHEEL SPEED SENSORS
Toyota Corolla Front Wheel Speed Sensor installed in the front suspension steering knuckle hole and removed as an assembly with the wiring harness.
Replacing the sensor on the left front wheel is shown. The sensor on the right front wheel is replaced in the same way.
2. Brake the rear wheels, install wheel chocks (“boots”) under them, loosen the front wheel fastening nuts, raise the front of the car, place it on reliable supports and remove the front wheel.
3. Remove the front wheel liner
4. Turn out a bolt of fastening of the gauge of frequency of rotation geredny wheel to a rotary fist.
5. Remove the sensor from the hole in the knuckle.
6. Using a screwdriver, open the lower latch and remove the sensor harness
7. Turn out a bolt and disconnect an arm of the lower fastening of a plait of wires from a rack of a forward suspension bracket.
8. Turn out a bolt and disconnect an arm of the top fastening of a plait of wires from a body.
9. Using a screwdriver, open the top latch and remove the front wheel speed sensor harness.
10. Wring out a clamp of fastening of a pad, disconnect a block of a plait of wires and remove the sensor of frequency of rotation of a forward wheel in gathering with a plait of wires.
11. Install the front wheel speed sensor and all removed parts in the reverse order of removal.
When installing the front wheel speed sensor, align the hole in the sensor housing exactly with the threaded hole in the knuckle. During installation, do not rotate the sensor around the longitudinal axis. An increase in resistance to the movement of the sensor should be felt only the last 2 mm before it is fully seated in the fist. If the sensor with high resistance enters the knuckle hole from the very beginning of installation, remove the sensor and eliminate the cause of jamming (dirt, burr on the housing, etc.)
It is strictly forbidden to press the wheel speed sensor with a hammer.
You will need: a screwdriver with a flat blade, wrenches "14", "17", socket head "14" with an extension cord.
Replacing the sensor on the left rear wheel is shown. The sensor on the right rear wheel is replaced in the same way.
1. Disconnect a wire from the minus plug of the storage battery.
2. Engage 1st gear (transfer the automatic transmission selector to the “P” position), install wheel chocks (“boots”) under the front wheels, loosen the rear wheel nuts, raise the rear of the car, place it on reliable supports and remove the rear wheel .
3. Prying off with a screwdriver, wring out the latch.
4 . .open and remove the rear wheel speed sensor housing.
5. Disconnect the rear wheel speed sensor harness connector.
6. Remove the brake caliper
7. Remove the brake disc
8. Remove the rear wheel hub
9. Install the rear wheel hub assembly with speed sensor and all removed parts in the reverse order of removal.
REMOVING THE HYDROELECTRONIC MODULE
: 1 - pipeline of the primary circuit of the main brake cylinder; 2 - pipeline of the second circuit of the main brake cylinder; 3 - pump; 4.5 - bolts for fastening the module to the bracket; b - bracket for attaching the module to the body; 7 - pipeline of the working brake cylinder of the right front wheel; 8 - pipeline of the working brake cylinder of the left rear wheel; 9 - pipeline of the working brake cylinder of the right rear wheel; 10 - pipeline of the working brake cylinder of the left front wheel; 11 - wiring harness block
The hydroelectronic module for controlling the anti-lock braking system is mounted on bracket 6 (Fig. 13.1) in the engine compartment on the left and attached to the bracket through rubber cushions with bolts 4 and 5.
And special keys "for 10", "for 14" for unscrewing the nuts of pipelines.
1. Disconnect a wire from the minus plug of the storage battery.
2. Pump out a brake liquid from a tank of the main brake cylinder
3. Turn away six nuts of fastening and disconnect pipelines of the hydroelectronic module.
4. Slide up the wire harness retainer.
5. Disconnect the wiring harness block from the hydro-electronic module.
6. Turn out two forward and one bottom bolt of fastening and remove the hydroelectronic module.
7. Install the hydroelectronic anti-lock brake control module and all removed parts in the reverse order of removal.
8. Bleed the brake system
Airbag layout: 1 - driver's airbag; 2 - passenger airbag; 3 - side airbags; 4 - curtains
Airbags actually installed in the vehicle may look different from the illustration.
The passive safety system (SRS) of a Toyota Corolla, Auris combines front 1 and 2 and side airbags 3 for the driver and passenger in the front seat, inflatable side curtains 4 (depending on configuration), height-adjustable seat belts for the driver and front passenger with pretensioners, retractable seat belts for rear passengers, ISOFIX child seat anchors, front seat with WIL rear impact protection system to prevent spinal injuries.
Airbags do not replace seat belts. Moreover, when the car is moving, the driver and front passenger must be sure to wear their seat belts, since in the event of a traffic accident, a deployed airbag itself can cause serious injury to a person who is not wearing a seat belt. In addition, passengers in the back seat must be fastened with seat belts. In the event of an accident, an unrestrained passenger in the rear seat can cause injury and serious injury to all passengers in the vehicle.
Do not install or place any accessories on the front panel in front of the passenger above the glove box in the vehicle. Such objects may move violently and cause injury if the passenger air bag inflates.
When installing an air freshener inside the passenger compartment, it should not be placed near appliances or on the surface of the dashboard. Such objects may move violently and cause injury if the passenger air bag inflates.
Deployment of airbags can be accompanied by a loud noise and the spread of fine dust throughout the cabin. This is normal as non-working airbags are packed in this powder. Dust generated during the opening of pillows can cause irritation to the skin or organs of vision, and increase the asthmatic reaction of some people. After an accident involving the deployment of airbags, thoroughly wash all exposed skin with warm water and soapy water.
The SRS airbag system is designed to deploy only when the force of the frontal impact is large enough and its direction is no more than 30 ° with the longitudinal axis of the vehicle. In addition, it is a disposable system. The front airbags are not designed to inflate in the event of a side impact, rear impact or vehicle rollover.
Children under the age of 12 must be transported in a special child restraint. The use of a child restraint is determined by the Rules of the Road, and its fastening in the passenger compartment is determined by the recommendations of the manufacturer.
It is the driver's responsibility to ensure that the passenger's front airbag switch is in the correct position. The passenger's front airbag should only be deactivated when the ignition is off, otherwise the airbag control unit may fail.
The SRS system includes the following elements:
The driver's airbag module, located in the steering wheel hub and consisting of a folded airbag shell and an inflator;
The driver's foot airbag module (optional) located at the bottom of the instrument panel;
The front passenger airbag module, located under the instrument panel on the passenger side, consists of a folded airbag shell and an inflator. Differs from the driver's airbag in shape and large volume;
Side airbag modules for the driver and front passenger located in the outer side parts of the front seat backs and consisting of a folded airbag shell and a gas generator;
Modules for driver and passenger air curtains (in a variant version) located under the facings of the front and rear pillars of the body and consisting of a folded airbag shell and a gas generator.
Airbag locations are marked with the "SRS AIRBAG" icon;
Front seat belt pretensioner modules, combined with inertial coils, located in the B-pillars, behind the lower pillar trim;
An electronic control unit installed in the instrument panel, under the control unit for the heating, air conditioning, and interior ventilation system.
The ECU incorporates micromechanical sensors that measure the longitudinal and lateral acceleration of the vehicle in a collision. The ECU evaluates the impact force by comparing the values it receives from the front impact sensors, side impact sensors, and internal electronic sensors with a predetermined value. If the deceleration signal due to a frontal or side impact exceeds a predetermined value, the ECU will trigger the seat belt pretensioners and deploy the corresponding airbags.
If the vehicle's battery ruptured during the crash, the voltage holding circuit in the ECU would still be able to activate the airbags for some time after the impact;
Frontal and side impact sensors that transmit acceleration information to the system control unit.
The side impact sensors are located on the B-pillar, behind the lower pillar trim.
The strength and direction of the impact in a traffic accident is determined by the electronic control unit (ECU) of the passive safety system using impact sensors. Based on the signals from the sensors, the control unit activates the airbags and front seat belt tensioners;
Seat belts. Upon impact of a certain force, the ECU, having received signals from the impact sensors, before activating the airbags, increases the tension of the belts, issuing a command to the pyrotechnic elements of the pretensioners. The latter provide a timely response to the emergency deceleration of the car, pulling the driver and front passenger to the seatbacks, exclude their further movement forward by inertia and injury from the deployed airbag;
Headrests installed in the backs of all seats prevent damage to the cervical vertebrae of people sitting in the car in the event of a strong rear impact and airbag deployment. The front seat head restraints feature WIL technology, further reducing the risk of neck and spinal injuries in a rear impact.
The front and rear seat headrests can be adjusted in height by pressing the lock and moving them up or down to the desired height.
The optimal position of the head restraint is when its upper edge is flush with the top of the head.
For very tall people, raise the head restraint to its highest position, for very short people, lower the head restraint to its lowest position.
- signaling devices of the passive safety system.
The VD passive safety system malfunction indicator (with a red light filter) is located on the right side of the instrument cluster. Lights up when the ignition is turned on, burns for about a bey and goes out if the system is working. If the indicator does not go out (or lights up while driving), then there is a malfunction in the passive safety system.
If the signaling device lights up, contact the car service immediately. In addition to the possible failure of the airbag in an emergency, it can unexpectedly deploy while driving, which will lead to serious consequences.
The airbag deactivation indicator A comes on and stays on when the passenger's front airbag is deactivated.
The airbag warning light B comes on and stays on if the passenger's front airbag is on.
The front passenger's seat belt warning lamp B illuminates and flashes when the ignition is switched on if the front passenger's seat belt is not fastened. The presence of a front passenger is detected by a special sensor in the front seat.
The driver's seat belt indicator is located on the right side of the instrument cluster, lights up and flashes when the ignition is on if the driver's seat belt is not fastened;
The front passenger airbag switch is located on the side
Surfaces of the instrument panel, on the right side of it. The switch deactivates the front passenger airbag when a child is in the front passenger seat.
Do not deactivate the front passenger airbag unnecessarily unless a child restraint is installed in the front seat.
This subsection describes the removal and installation of the driver and front passenger airbags, the removal and installation of seat belts. Side airbags and curtain airbags should only be removed at a workshop by specially trained personnel.
You will need: Flat blade screwdriver, TORX T3O wrench.
1. Disconnect a wire from the minus plug of the storage battery.
Before changing the fuse or disconnecting the battery, turn the ignition key to the "LOCK" position and remove it from the ignition. Never remove or replace fuses related to the airbag system with the ignition key in the "ON" position. Failure to heed this warning will cause the airbag warning light to come on. To turn off the alarm, you will have to contact a specialized auto repair center.
2. Having prying off a screw-driver, wring out clamps and remove plugs from the left and right side of a steering wheel.
3. Using the TORX TZO key, turn out the screws securing the steering wheel pad on the left and right sides.
4. Pull and remove the airbag cover from the steering wheel
5. Disconnect the horn terminal from the inside of the steering wheel pad.
6. Prying off with a screwdriver, pull out the retainer of the airbag wiring harness block ...
7. ... Disconnect the wiring harness block and remove the airbag.
Do not disassemble the airbag module.
Do not drop the airbag module or allow water, grease or oil to come into contact with it.
The airbag module must not be exposed to temperatures above 95°C.
8. Install the driver's airbag and all removed parts in the reverse order of removal.
When installing the module in the steering wheel of a car, stay outside the airbag deployment area.
REMOVING AND INSTALLING THE FRONT PASSENGER AIRBAG
You will need: screwdrivers with a flat and Phillips blade, a “10” wrench.
1. Disconnect a wire from the minus plug of the storage battery.
Attempting to remove the airbag module without disconnecting its power supply may cause the airbag to deploy unexpectedly.
It is possible to proceed with subsequent operations to remove the airbag only after the activator capacitor is completely discharged. To discharge the capacitor, you must wait at least one minute after turning off the power supply.
2. Remove the upper part of the instrument panel
3. From the inside of the instrument panel, remove the two screws securing the airbag brackets
4. Detach the front and rear brackets..
5. ... and remove the airbag.
Do not disassemble the airbag module.
Do not drop the airbag module or allow water, grease or oil to come into contact with it.
The airbag module must not be exposed to temperatures above 95°C.
6. Install the front passenger airbag and all removed parts in the reverse order of removal.
When you turn on the ignition for the first time after installing the airbag module in the vehicle, be outside the vehicle and turn on the ignition switch by reaching under the steering column.
REMOVAL AND INSTALLATION OF THE ELECTRONIC CONTROL UNIT OF THE PASSIVE SAFETY SYSTEM
You will need: screwdrivers with a flat and cross-shaped blade, keys "10", "12".
For clarity, the work is shown on a car with the instrument panel removed.
1. Disconnect a wire from the minus plug of the storage battery.
After disconnecting the wire from the "minus" terminal of the battery, you must wait at least a minute, and only after that you can disconnect the ECU wiring harness block.
2. Remove the lining of the floor tunnel
3. On the center console, remove the ashtray unit, the security system indication unit, the heating, air conditioning and interior ventilation control unit
4. Overcoming resistance of clamps, disconnect the central air duct from the block of system of heating, conditioning and ventilation of salon and remove an air duct.
5. Press the lever lock and turn the wiring harness lock lever to the left
6. Disconnect the ECU harness block
7. Turn out a bolt of forward fastening of EBU
8. Turn out the left and right bolts of back fastening of ECU.
9. Pull towards you and remove the electronic control unit for the passive safety system.
10. Install the SRS control unit and all removed parts in the reverse order of removal.
Toyota Corolla shock sensor replacement
You will need: screwdrivers with a flat and Phillips blade, a “10” wrench.
To replace the side impact sensor, do the following.
1. Disconnect a wire from the minus plug of the storage battery.
Left Side Impact Sensor Replacement Shown.
The side impact sensor on the right side is replaced in the same way.
2. Remove the bottom facing of the central rack of a body
3. Slide the wire harness retainer...
4. ... and disconnect the block of the side impact sensor.
5. Turn out a bolt of fastening of the gauge to the central rack of a body.
6. Remove the side impact sensor.
7. Install the side impact sensor and all removed parts in the reverse order of removal.
Follow the steps below to replace the front impact sensors.
1. Disconnect a wire from the minus plug of the storage battery.
After disconnecting the wire from the "minus" terminal of the battery, you must wait at least one minute, and only after that you can proceed to remove the sensor.
Front impact sensors are located on the side members of the car body in front of the engine compartment.
Replacing the front impact sensor on the left side of the vehicle is shown.
Anti-lock braking system (ABS, ABS) is an automated system that prevents the car's wheels from blocking in the event of braking. The main task of the system is to ensure the controllability of the vehicle during heavy braking. Also, the action of abs is aimed at eliminating the possibility of uncontrolled sliding of the car.
The principle of operation of the anti-lock braking system (abs, abs) is as follows: at the beginning of braking, when the brake system is activated, the sensors installed on the wheels of the car determine the beginning of the moment of a sharp stop (blocking) of the wheels and, through feedback, the braking force is weakened, which allows the wheel to turn and enter into engagement with the roadway. In this case, preventive measures for determining the moment of slip are applied in order to prevent even short-term slip.
The following components are an integral part of the anti-lock braking system:
Speed sensors installed on the wheels of the car, determining the speed;
Control valves, in the main line of the vehicle's brake system;
A feedback unit that receives signals from sensors on the wheels and regulates the operation of the valves.
For an inexperienced driver, having ABS is better anyway, as it allows emergency braking in an intuitive way, simply by applying maximum force to the brake pedal, while maintaining maneuverability.
The main disadvantage of modern ABS is braking on loose sections of the road (high snow, gravel, sand). The braking distance becomes longer than when the wheels are completely blocked, since the car does not “dig in” into the coating, but continues to move. However, modern ABS have algorithms that are applied when braking on loose surfaces.
GENERAL INFORMATION
Arrangement of elements of system of antiblocking brakes (ABS)
The Anti-Lock Brake System (ABS) is designed to maintain vehicle control, stability, and maintain optimum deceleration during hard braking under most road conditions. This is done by monitoring the rotation speed of each of the wheels and adjusting the brake fluid pressure for each of the wheels. This prevents the wheels from locking up.
SYSTEM ELEMENTS
Drive unit
The ABS drive system consists of a hydraulic pump and four solenoid valves. The pump creates hydraulic pressure in the drive cavities, which creates pressure in the brake system. The pump and cavities are located in the drive housing. Solenoid valves regulate the pressure in the brake system when the ABS system is activated. There is one valve for each wheel.
Wheel speed sensors
The wheel speed sensors that are on each wheel generate small electrical pulses as the gear rotors rotate, sending various voltage signals to the ABS ECM to indicate wheel speed.
The front wheel speed sensors are mounted on the steering knuckles of the front wheels, next to the toothed rotors mounted on the outer pivots of the axle shafts.
The rear wheel speed sensors are attached to the rear brake pads or hub brackets. The sensor rotors are mounted on the rear wheel hubs.
ABS computer
The ABS electronic control unit is located under the instrument panel and is the brain of the ABS system. The electronic control unit receives and processes information received from the wheel speed sensors and controls the pressure in the brake system, preventing the wheels from locking. The electronic control unit also constantly monitors the operation of the system to monitor the occurrence of malfunctions.
If a malfunction occurs in the system, the ABS warning light on the instrument panel lights up. The fault code is also stored in the electronic control unit and will indicate to specialists the area or element of the system that has failed.
DIAGNOSIS AND REPAIR
If the warning light on the instrument panel comes on and stays on while the vehicle is moving, the ABS system needs attention. Although a special electronic ABS diagnostic tester is required to accurately diagnose the ABS system, the car enthusiast can carry out the following preliminary checks on their own before contacting a body shop:
- Check up level of a brake liquid in a tank; - check the reliability of wire connections; - check the fuses
In Toyota vehicles equipped with electronic control units (ECU) of the engine, automatic transmission, ABS, etc., the possibility of self-diagnosis is provided. The principle of operation of this system is as follows:
On modern Toyota Corolla cars, the ECU is able to distinguish between malfunctions according to the degree of importance for operation, and information about "light" deviations is not recorded. For example, if dirt gets on one of the ABS sensors while driving, and after washing it off, the sensor switches back to normal operation, this deviation will not be recorded.
- 1 Connectors for diagnostics of Toyota Corolla cars
- 2 Ways to read information during self-diagnosis of a car
- 3 Varieties of two-digit codes
- 4 Two-digit system codes
- 4.1 Powerplant Fault Codes
- 4.2 Error codes for ABS and TRC systems (code 10)
- 5 OBD codes
- 6 How to reset error data after diagnostics?
DLS 1 is a rectangular plastic box located under the car's hood on the left. This connector has a corresponding designation on the body - "DIAGNOSTIC". Self-diagnosis is carried out using the "CHECK" light located on the instrument panel, the corresponding control lights of the car's systems or other signaling devices.
The DLS 2 diagnostic connector is located in the passenger compartment: under the front panel on the driver's side. It has a different configuration than DLS 1, as it involves the connection of special diagnostic equipment. This connector is convenient in that it allows self-diagnosis of a running car.
Ways to read information during self-diagnosis of a car
- In the first case, for self-diagnosis, they use the closure of the corresponding terminals of the DLC connectors with a wire or with a regular straightened paper clip. To do this, we find the connector marked DIAGNOSTIC and open its cover. There is a pin marking diagram on the back of the cover. With the help of a wire, we close the conclusions "E1" and "TE1" on DLC 1, or the conclusions "TC" and "CG" on DLC 3. After that, turn on the car's ignition and watch the corresponding lights flash on the instrument panel.
- For diagnostics, special diagnostic devices can also be used: scanners or testers. Some service stations have special diagnostic computers. These devices are expensive, but in addition to complete diagnostics, they allow programming various systems and reading signals from various nodes in real time.
For self-diagnosis of cars, two types of two-digit codes are most often used: the first is type 09; the second is type 10.
Frequent and continuous flashing of the warning light, with a flash and a pause of 0.5 seconds, indicates that the vehicle uses code type 09. If the light flashes more than 11 times when using this code, then no fault records have been found.
Two-Digit System Codes
Explanation of engine fault codes for type 09:
Error codes for ABS and TRC systems (code 10)
OBD Codes
The first character of this code is called the Alpha Pointer and indicates the system in which the fault occurred:
The following numbers indicate the exact location and classification of the problem.
In order to prevent the car's wheels from locking and, as a result, skidding on the road, Toyota Corolla uses an anti-lock braking system. The purpose of a fully automated anti-lock system is to maintain controllability in the event of an emergency braking of the car, to exclude its uncontrolled slipping.
Rice. 1. Paths of deceleration during deceleration
Anti-blocking works according to the following principles:
- at the initial moment of braking, special sensors on the wheels record the initial blocking impulse;
- by feedback on the electric wire, a signal is generated that controls the weakening of the force of the hydraulic cylinders even before the start of slippage, the tires again enter the grip;
- after spinning the wheel, the maximum braking force is again created in the hydraulic cylinders;
Due to the repeated repetition of this simple electro-hydromechanical chain, the braking distance is practically no greater than with continuous blocking, but controllability is completely preserved. This allows you to avoid skidding, moving the car into the oncoming lane or onto the side of the road.
ABS complex device
The main components of the anti-blocking system:
- speed sensors front and rear wheels;
- hydraulic valves of the hydraulic system of brakes;
- elements of the sensor information exchange channel with hydraulic system valves.
Anti-lock braking is especially important for inexperienced drivers, as all you have to do is hold the brake pedal to the floor and the system does the rest. But on sections of the road with a loosened surface in the form of gravel, sand or snow, the braking distance turns out to be greater than when braking by completely and continuously blocking the brakes. After all, the tires do not burrow into the loose mass, but slip along its surface.
Rice. 2. Places of installation of ABS units in the car
On fig. 2 shows the layout of the main components of the auto-lock system in the overall structure of the car.
The arrows indicate the following elements:
- Anti-blocking complex drive;
- Control relay;
- Control unit and photodiode for turning on the anti-lock braking system;
- Front wheel speed sensor;
- Speed sensor rotor in the front wheel;
- Speed sensor rotor in the rear wheel;
- Rear wheel speed sensor.
The action of the anti-lock complex is reduced to maintaining the stability and controllability of the machine with an optimal decrease in speed. All this happens by monitoring the speed of rotation of each wheel and periodically relieving pressure in its brake hydraulic line.
ABS electronic module
The anti-lock control unit is located next to the dashboard. It includes and processes electrical impulses from wheel speed sensors. After processing the information, the node sends signals to the cavity valves of the anti-blocking drive.
Also, with the help of an electronic module, the performance of the entire complex is constantly monitored and tested. In the event of a malfunction, a light signal flashes on the instrument panel to alert the driver to an abnormal situation. Also, the electronics unit is able to generate a fault code and store it for a service station specialist.
A photodiode signal flashing from time to time warns the driver that deviations in operating parameters are possible in the complex. In this case, you should check the reliability of the connection of wires from the sensors to the electronic unit, fuses, filling the reservoir of the main brake cylinder with brake fluid.
If after that the warning signals continue to appear, then you should contact a specialized Toyota Corolla repair and maintenance center.
Toyota Corolla anti-lock braking system drive
The device includes a hydraulic pump and a multi-cavity housing with four solenoid valves. In the drive cavity of each wheel, the required pressure is created and regulated using its own valve. The signals for opening and closing cavity valves come from wheel rotation sensors.
Photo 1. Toyota Corolla Fielder ABS unit
The block can be seen under the hood of the engine compartment. It is located next to the brake cylinder and is connected to it with metal pipes for the flow of brake fluid.
Wheel speed sensors
These elements are mounted on the fists of the front wheels. They are located close to the gear rotors of the external connections of the axle shafts and the back of the wheels fixed on the brake flaps with the rotors on the wheel hubs, constantly send information in the form of electrical impulses to the ABS electronic module.
Rice. 3. Toyota Corolla front wheel speed sensor
Anti-lock system operation signals
The driver learns about the operation of the system by a specific twitching of the brake pedal at the time of braking and by a flashing light on the instrument panel. If the light starts to burn continuously, then this means a malfunction in the anti-lock complex. However, you should not sound the alarm at the same time - after all, in case of malfunctions in the ABS, the braking system works like in all cars without anti-lock.
To turn off the anti-lock complex in some Toyota Corolla models, it is enough to press the brake pedal many times as during intermittent braking. In the same way, a new inclusion of the complex into operation is carried out.
