The Toyota Corolla is equipped with a set of security systems designed to reduce the likelihood of emergency, and in the event of a traffic accident - maximum protection driver and passengers.
ABS- anti-lock system brakes. Prevents wheel lock emergency braking or when braking on a slippery road.
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 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 the vehicle speed, direction of travel and road conditions from the wheel speed sensors and the position sensor throttle valve. 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. Under normal braking inlet valve open, outlet valve closed. When the brake pedal is pressed, brake fluid is supplied under pressure to the working cylinder and actuates brake mechanisms 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 exhaust 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.
For diagnostics and repair of the anti-lock braking system, special equipment and equipment, therefore, in case of failure, contact a specialized service station.
If the anti-lock brake system warning light comes on in the instrument cluster, diagnostic code you can determine the cause of the system failure. 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. Install 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
Speed sensor front wheel Toyota Corolla 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 top mount wiring harness from the 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 (move the selector automatic box shifting to the “P” position), install wheel chocks (“boots”) under the front wheels, loosen the nuts securing the rear wheel, lift 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"on 10", "on 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.
System passive safety(SRS) of a Toyota Corolla, Auris combines front 1 and 2 and side airbags 3 for the driver and front passenger, inflatable side curtains 4 (depending on configuration), height-adjustable seat belts for the driver and front passenger with pretensioners, inertial belts security for rear passengers, ISOFIX child seat attachments, 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 glove box in the car. 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 inflate only when the force frontal impact is large enough and its direction makes an angle of 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;
Driver and passenger air curtain modules (optional) located under the front and rear pillars body and consisting of a folded pillow 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.
Head restraints front and rear seats can be adjusted in height by pressing the latch 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 top heads.
For very tall people, raise the head restraint as far as possible. top 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. Prying with a screwdriver, wring out the latches and remove the plugs from the left and right side 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 the resistance of the clamps, disconnect the central air duct from the block of the heating, air conditioning and ventilation system and remove the air duct.
5. Press the lever lock and turn the wiring harness lock lever to the left
6. Disconnect the ECU harness block
7. Remove the bolt front mount ECU
8. Turn out the left and right bolts of back fastening of EBU.
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.
ABS (Anti-Lock Braking System) is required to prevent the vehicle's wheels from locking up during braking and skidding.
In general, this system eliminates the occurrence of uncontrolled slippage of the car during emergency braking. In addition, with the help of ABS, the driver can control the vehicle even during emergency braking.
ABS works according to the following principle:
- Sensors mounted on the wheels, during the initial stage of braking, record the initial blocking impulse.
- With the help of "feedback" an electrical impulse is formed, which is transmitted through an electric wire, this impulse weakens the efforts of the hydraulic cylinders even before the moment the slip begins, and the tires of the car are again in grip with the road surface.
- After the wheel has finished spinning, the maximum possible braking force is again created in the hydraulic cylinders.
This process is cyclic, it is repeated many times. Thanks to this, the braking distance of the car remains exactly the same as it would be with continuous blocking, but the motorist does not lose control of the steering.
The safety of the driver and passengers is increased, since the possibility of the vehicle skidding and taking it into a ditch or into the oncoming lane is excluded.
The ABS of a car consists of the following parts:
- sensors responsible for speed, they are installed on the front and rear wheels Oh;
- brake valves operating on the hydraulic principle;
- devices designed to exchange information between sensors and valves of a hydraulic system.
Thanks to ABS braking, even inexperienced drivers will be able to cope with their vehicle. To do this, on a Toyota car, it will only be necessary to press the brake pedal to the floor “all the way”. It should also be taken into account that the road surface with a loose coating contributes to the fact that the car has a much longer braking distance. After all, the wheels do not burrow into a loose surface, but only slip over it.
ABS installed on cars foreign production such as the Toyota Corolla. The main essence of the action of such a system is to maintain the stability and controllability of the vehicle, while reducing the speed in the most optimal proportion. This is due to the fact that on the Toyota Corolla model, sensors “monitor” the speed at which each wheel of the car rotates, then pressure is released in the brake hydraulic line.
In Toyota cars, the control unit is located near the dashboard. The principle of operation of the control unit is that it includes electrical impulses coming from speed sensors located on the wheels of the vehicle.
After the electrical impulse has been processed, the signal is sent to the actuator valves responsible for anti-blocking. A special electronic module constantly captures and monitors the performance of the entire ABS system. If any malfunctions suddenly arise, then a light on the instrument panel lights up, thanks to which the driver learns about the breakdown.
In addition, the ABS system allows you to generate and store a fault code. This will greatly facilitate the repair in the service station. Toyota Corolla is equipped with a diode that notifies you of a breakdown. In addition to it, a special photodiode signal may flash from time to time. Thanks to him, the driver learns that in the ABS complex some “breaks” in operating parameters are possible.
In order to correct the failure of the settings and parameters, it is necessary to check whether the wires that go from the sensors to the electronics unit are securely connected, the condition of the fuse and the fullness of the reservoir related to the main brake cylinder are also checked.
Even if after all these operations the warning signals continue to flash, then the ABS system is faulty and the owner of the Toyota Corolla should contact a specialized service center.
So the components car ABS from a Japanese manufacturer. The anti-lock drive consists of:
Anti-lock braking system (ABS, ABS) - automated system preventing blocking of the wheels of the car in case of braking. The main task of the system is to ensure the controllability of the vehicle when hard braking. Same way abs action designed to eliminate the possibility of uncontrolled slipping 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 sudden stop (blocking) of the wheels and, through feedback, weakening occurs braking force, which allows the wheel to turn and engage with carriageway. In doing so, apply preventive measures detection of the moment of slippage in order to prevent even short-term slippage
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 inexperienced driver ABS is better in any case, as it allows emergency braking in an intuitive way, simply by applying maximum force to the brake pedal, while maintaining the ability to maneuver
The main disadvantage of modern ABS is braking on loose sections of the road (high snow, gravel, sand). Braking distances 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 optimal deceleration during hard braking under most road conditions. This is done by monitoring the rotational 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 the 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.
Rear wheel speed sensors are attached to the shields rear brakes 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 fault occurs in the system, a warning light will illuminate on the instrument panel. abs light bulb. The fault code is also stored in electronic unit management 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 tester is needed to accurately diagnose the ABS system ABS diagnostics, the car enthusiast can carry out the following preliminary checks on their own before contacting a car repair shop:
- Check up level of a brake liquid in a tank; - check the reliability of wire connections; - check the fuses
Diagnostics of ABS failures
Control panel connection diagram ABS lampsABS failures of the driver are signaled by a special control lamp located on the dashboard of the car. As soon as the ABS control module detects a violation in the system, it turns it off. The braking system continues to function normally.
Diagnostics of the ABS condition is performed every time the engine is started and is accompanied by a short-term operation of the control lamp. Within a short time after starting, the lama should automatically turn off.
If the ABS warning light comes on and stays on while driving, first check that parking brake fully released and the brake system is functioning properly. If everything is normal, then the ABS has failed. Do the following simple checks first:
a) Check the condition of the brake calipers and wheel cylinders;
b) Check up a condition and reliability of fastening of contact sockets of electroconducting of the control module ABS and wheel gauges (see the Head Onboard electrical equipment);
c) Check the appropriate fuses (see Chapter Onboard electrical equipment).
Failures of a control lamp ABS
The cause of failures in the functioning of the ABS warning lamp may be an open or short circuit in its electrical circuit.
The ABS warning lamp does not come on when the ignition is switched on
Try to turn on the ignition without starting the engine - if the other indicator lamps that are part of the instrument cluster work properly, proceed to the next step of the test, otherwise the necessary restorative device of the instrument panel should be made.
Switch off the ignition. Remove the instrument cluster, remove the ABS warning lamp and check its condition. If the lamp is burned out, replace it, otherwise proceed to the next step of the test.
Disconnect the contact pair B62 / F45 and measure the voltage between the chassis ground (-) and terminal No. G6 (+) of the B62 connector. If the measurement result is less than 3 V, proceed to the next test step, otherwise, check the condition of the wiring of the corresponding control lamp. Make necessary repairs.
Turn off the ignition, put the control lamp under test in its original place and install the instrument cluster.
Turn on the ignition and repeat the voltage measurement. If the measurement result does not fall outside the range of 10 ÷ 15 V, proceed to the next step of the test, otherwise check the condition of the wiring. Produce the required refurbishment.
Switch off the ignition and perform a voltage test between terminal G6 (+) of connector F45 and chassis ground. If the measurement result is less than 3 V, proceed to the next test step, otherwise check the condition of the relevant wiring. Make necessary repairs.
Switch on the ignition and repeat the test. If the measurement result is less than 3 V, proceed to the next test step, otherwise, check the condition of the wiring of the corresponding control lamp. Make necessary repairs.
Measure the resistance between terminal No. 23 of connector F49 and ground. If the measurement result is less than 5 ohms, proceed to the next step of the test, otherwise, check the grounding of the control module / hydromodulator assembly. Make necessary repairs.
Measure the resistance between ground and terminal G6 connector F45. If the measurement result is less than 5 ohms, proceed to the next test step, otherwise check the condition of the connector and its wiring harness. Make the necessary remedial repairs, if necessary, replace the connector.
Switch off the ignition and check the condition of the connectors in the circuit section between the instrument cluster and the ABS control module - if there are no signs of poor contact reliability, replace the ABS control module / hydraulic modulator assembly.
The ABS warning lamp does not turn off after starting the engine
Switch off the ignition and make sure that the ABS control module/hydraulic modulator connector is fully seated and securely fixed.
Measure the resistance between chassis ground and each (A and B) of the diagnostic terminals (B81). If the measurement result is less than 5 ohms, proceed to the next step of the test, otherwise, check the condition of the corresponding wiring harness, make the necessary remedial repairs.
Switch off the ignition and connect the diagnostic terminal to terminal No. 8 of the B82 diagnostic connector. Disconnect the ABS control module connector and measure the resistance between connector F49 terminal No. 4 and chassis ground. If the measurement result is less than 5 ohms, proceed to the next step of the test, otherwise check the condition of the wiring in the circuit section between the ABS control module and the diagnostic connector, make the necessary remedial repairs.
Start the engine on idling and check for voltage between the B (+) terminal on the rear of the generator (power terminal) and chassis ground. If the measurement result is within the range of 10 ÷ 15 V, proceed to the next step of the test, otherwise replace/repair the generator (see Chapter ) and repeat the test.
Turn off the ignition and check the condition of the battery terminals and the reliability of the terminal lugs of the wires on them. Make the necessary corrections if necessary.
Disconnect the ABS control module wiring connector, then start the engine at idle and measure the voltage between terminal No. 1 (+) of connector F49 and chassis ground. If the measurement result is within the range of 10 ÷ 15 V, proceed to the next step of the test, otherwise check the condition of the wiring of the power supply circuit. Make necessary repairs.
Disconnect the contact pair B62 / F45 and turn on the ignition - if the ABS warning lamp does not work, proceed to the next step of the test, otherwise check the condition of the front wiring harness.
Switch off the ignition and check the condition of the tabs on the control module connector. If the terminals are in order, proceed to the next step of the test, otherwise, replace the control module / hydromodulator (see Section ).
Measure the resistance between terminals No. 22 and 23 of the ABS control module connector. If the measurement result is more than 1 MΩ, proceed to the next step of the test, otherwise replace the ABS control module/hydraulic modulator assembly (see Section Removal, installation and check of serviceability of functioning of assembly of the control module / hydraulic modulator ABS).
Measure the resistance between terminal G6 of connector F45 and chassis ground. If the measurement result is less than 0.5 ohm, proceed to the next step of the test, otherwise, make the necessary reconditioning of the wiring.
Connect the wiring to the ABS control module and measure the resistance between terminal G6 of connector F45 and chassis ground. If the measurement result is more than 1 MΩ, proceed to the next step of the test, otherwise, make the necessary reconditioning of the wiring.
Check the condition and security of the ABS control module connector. If necessary, make the necessary corrections, or replace the control module / hydromodulator assembly.
Unable to read fault codes
If the test lamp turns on and off normally, but does not display the initial code (DTC 11 - see below) when entering the diagnostic mode, turn off the ignition and perform the checks.
Wheel sensor failures
Failures of wheel sensors lead to violation of serviceability of functioning of ABS. The connection diagram of the wheel sensors is shown in the illustration.
An open in the wheel sensor circuit or an excessively high input voltage level (DTC Nos. 21, 23, 25 and 27)
Disconnect the wiring from the ABS control module and measure the voltage between the appropriate wheel sensor terminal No. 1 and chassis ground. If the measurement result is less than 1 V, proceed to the next test step, otherwise replace the sensor.
Switch on the ignition and repeat the previous test. If the measurement result is less than 1 V, proceed to the next test step, otherwise replace the sensor.
Turn off the ignition and connect the wiring to the sensor. Measure the resistance between terminals Nos. 11 and 12 (DTC 21)/9 and 10 (DTC 23)/14 and 15 (DTC 25)/7 and 8 (DTC 27) of connector F49. If the measurement result is within the range of 1 ÷ 1.5 kOhm, proceed to the next step of the test, otherwise check the condition of the wiring in the area between the control module and the sensor. Make necessary repairs.
Measure the voltage between ground and terminal No. 11 (DTC 21)/9 (DTC 23)/14 (DTC 25)/7 (DTC 27) of connector F49. If the measurement is greater than 1 V, repair the short in the circuit between the sensor and the ABS control module. If there is no voltage (less than 1 V), turn on the ignition and repeat the test. If there is still no voltage (less than 1 V), proceed to the next step of the test, otherwise check the condition of the wiring between the sensor and the ABS control module, if necessary, eliminate the cause of the short circuit.
Measure the gap between the sensor and the rotor around the entire perimeter of the latter. In case of insufficient clearance (see. Specifications) adjust it by selecting an adjusting shim (26755АА000). If the gap is too large, remove the spacers and replace the rotor (assembly with swivel assembly) or failed sensor. After completing the adjustment, proceed to the next step of the test.
Ignition OFF, and measure the resistance between the wheel sensor connector terminal #1 and chassis ground. If the measurement result is more than 1 MΩ, proceed to the next test step, otherwise replace the sensor.
Switch off the ignition and connect the wiring to the wheel sensor. Measure the resistance between chassis ground and terminal No. 11 (DLC 21)/9 (DLC 23)/14 (DLC 25)/7 (DLC 27) of connector F49. If the measurement result is more than 1 MΩ, proceed to the next step of the test, otherwise check the condition of the wiring in the section of the circuit between the sensor and the ABS control module. Make necessary repairs. If the wiring is OK, replace the control/hydraulic modulator assembly.
Restore the original connection of all connectors, clear the processor memory (see below) and repeat the procedure for reading diagnostic codes. If no change (in the direction of improvement) has occurred, replace the ABS control module/hydraulic modulator assembly. If new codes appear, proceed to perform the appropriate check. If the failure did not repeat, therefore, the malfunction was temporary, - once again make sure that all contact connections are securely fastened.
Short in wheel sensor circuit (DTC #22, 24, 26 & 28)
Switch off the ignition and check the tightness of the sensor mounting bolts (32 Nm). Tighten the fasteners if necessary and proceed to the next step of the test.
If you can't use an oscilloscope, move on to checking the mechanical condition of the rotor and cleaning the components.
If you have an oscilloscope, jack up the car and place it on jack stands so that the wheels are completely off the ground. Turn off the ignition and connect an oscilloscope between terminals No. C5 (+) and B5 (-) (DTC 22) / C6 (+) and B6 (-) (DTC 24) of connector B62 or 1 (+) and 2 (-) (DTC 26)/4 (+) and 5 (-) (DTC 28) connector F55.
Turn on the ignition and, while rotating the corresponding wheel of the car, follow the oscilloscope readings. The amplitude of the sinusoidal signal displayed on the screen should not exceed the range of 0.12 ÷ 1.00 V, - if this condition is not met, or the signal has an irregular shape, proceed to the next step of the test.
Check wheel hub runout. If the measurement result is less than 0.05 mm, proceed to the next step of the test, otherwise replace the hub.
Switch off the ignition. Disconnect the wiring from the appropriate wheel sensor. Measure the resistance between terminals No. 1 and 2 of the sensor connector. If the measurement result is within the range of 1 ÷ 1.5 kOhm, proceed to the next step of the test, otherwise replace the sensor.
Measure the resistance between ground and terminal No. 1 of the wheel sensor connector. If the measurement result is more than 1 MΩ, proceed to the next test step, otherwise replace the sensor.
Connect the wiring harness to the wheel sensor and disconnect it from the ABS control module. Measure the resistance between terminals Nos. 11 and 12 (DTC 22)/9 and 10 (DTC 24)/14 and 15 (DTC 26)/7 and 8 (DTC 28) of connector F49 of the ABS control module. If the measurement result is within the range of 1 ÷ 1.5 kOhm, proceed to the next step of the test, otherwise, perform the necessary reconditioning of the wiring in the circuit section between the sensor and the ABS control module / hydromodulator.
Measure the resistance between chassis ground and terminal No. 11 (DTC 22)/9 (DTC 24)/14 (DTC 26)/7 (DTC 28) of connector F49 of the control module. If the measurement result is more than 1 MΩ, proceed to the next test step, otherwise check the wiring between the sensor and the module for a short circuit. Make necessary repairs.
Measure the resistance between ground and terminal No. 23 of connector F49. If the measurement result is less than 0.5 ohm, proceed to the next step of the test, otherwise, eliminate the cause of the ground fault.
Check up reliability of fastening of contact sockets of the module of management ABS and the wheel sensor. Make the necessary corrections. If the contacts are in order, proceed to the next step of the test.
Make sure the car phone/remote control transmitter is installed at a sufficient distance from the wheel sensor wiring harness.
Restore the original connection of all connectors and measure the resistance between ground and terminal No. A5 (DTC 22) / A6 (DTC 24) of connector B62. If the measurement result is less than 0.5 ohm, proceed to the next test step, otherwise replace the shielded harness.
Restore the original connection of all connectors and repeat the procedure for reading diagnostic codes. If no change (in the direction of improvement) has occurred, replace the ABS control module/hydraulic modulator assembly. When new codes appear, go to the appropriate test. If the failure did not repeat, therefore, the malfunction was temporary, - once again make sure that all contact connections are securely fastened.
There are problems with the correct output of the wheel sensor (one or all four) of the information signal (DTC 29)
Assess the condition of the tread and tire inflation pressure. Make appropriate corrections/replacements if necessary.
Check the tightness of the mounting bolts ABS sensors(32 Nm). Tighten the fasteners if necessary and proceed to the next step of the test.
Measure the gap between the sensor and the rotor around the entire perimeter of the latter. In case of insufficient clearance (see Specifications), correct it by selecting an adjusting shim (26755AA000). If the gap is too large, remove the spacers and replace the rotor (assembly with swivel assembly) or failed sensor. After completing the adjustment, proceed to the next step of the test.
If you can't use an oscilloscope, move on to checking the mechanical condition of the rotor and cleaning the components. If you have an oscilloscope, jack up the car and place it on jack stands so that the wheels are completely off the ground. Turn off the ignition and connect an oscilloscope between terminals No. C5 (+) and B5 (-) (DTC 22) / C6 (+) and B6 (-) (DTC 24) of connector B62 or 1 (+) and 2 (-) (DTC 26)/4 (+) and 5 (-) (DTC 28) connector F55.
Turn on the ignition and, while rotating the corresponding wheel of the car, follow the oscilloscope readings. The amplitude of the sinusoidal signal displayed on the screen should not exceed the range of 0.12 ÷ 1.00 V, - if this condition is not met, or the signal has an irregular shape, proceed to the next test stage, otherwise proceed to the next test.
Carefully inspect the wheel sensor and its rotor for signs of damage or contamination. Wipe components, fix any problems.
Check wheel hub runout. If the measurement result is less than 0.05 mm, proceed to the next step of the test, otherwise replace the hub.
Switch off the ignition. Restore the original wiring connection. Clear the processor memory (see below) and repeat the procedure for reading diagnostic codes. If no change (in the direction of improvement) has occurred, replace the ABS control module/hydraulic modulator assembly. When new codes appear, go to the appropriate test. If the failure did not repeat, therefore, the malfunction was temporary, check again the reliability of fastening of all contact connections.
Failures of the control module / hydraulic modulator ABS
Intake (DTC 31, 33, 35 & 37) / Exhaust (DTC 32, 34, 36 & 38) Solenoid Valve Malfunction
Disconnect the wiring from the ABS control module.
Start the engine at idle and measure the voltage between terminal No. 1 (+) of connector F49 of the control unit and chassis ground. If the measurement result is within the range of 10 ÷ 15 V, proceed to the next step of the test, otherwise check the condition of the wiring between the battery, the ignition switch and the ABS control module. Make necessary repairs.
Switch off the ignition and measure the resistance between chassis ground and terminal No. 23 of connector F49. If the measurement result is less than 0.5 ohm, proceed to the next step of the test, otherwise, eliminate the cause of the ground fault.
ABS Control Module Malfunction (DTC 41)
Switch off the ignition. Disconnect the wiring from the ABS control module and measure the resistance between terminal No. 23 of connector F49 and chassis ground. If the measurement result is less than 0.5 ohm, proceed to the next step of the test, otherwise, eliminate the cause of the ground fault.
Check up serviceability of a condition and reliability of fixing of contact sockets of electroconducting on the control module ABS, the generator and the storage battery. Carry out appropriate reconditioning if necessary. If there are no violations of the quality of contacts, proceed to the next step of the test.
Make sure the car phone/remote control transmitter is installed at a sufficient distance from the ABS wiring harnesses.
Switch off the ignition. Restore the original wiring connection. Clear the processor memory and repeat the procedure for reading diagnostic codes. If no change (in the direction of improvement) has occurred, replace the ABS control module/hydraulic modulator assembly. When new codes appear, go to the appropriate test. If the failure did not repeat, therefore, the malfunction was temporary, - once again make sure that all contact connections are securely fastened.
Deviation from the nominal supply voltage level (DTC 42)
Start the engine and warm it up to normal operating temperature. Check that the idle speed is set correctly. Measure the voltage between the B (+) terminal on the rear of the generator and chassis ground. If the measurement result does not fall outside the range of 10 ÷ 17 V, proceed to the next step of the test, otherwise check the state of the charging system (see Chapter Engine electrical equipment
), make the necessary corrections.
Turn off the ignition and check the condition of the battery terminals and the reliability of fixing the terminal lugs of the wires on them. If necessary, clean the contact surfaces of the terminals/lugs. If the terminals are OK, disconnect the wiring from the ABS control module, start the engine at idle and measure the voltage between ground and terminal No. 1 (+) of the F49 connector. If the measurement result is within the range of 10 ÷ 17 V, proceed to the next step of the test, otherwise check the condition of the wiring between the ignition switch and the ABS control module connector. Make necessary repairs.
Switch off the ignition and measure the resistance between terminal No. 23 of connector F49 and chassis ground. If the measurement result is less than 0.5 ohm, proceed to the next step of the test, otherwise, eliminate the cause of the ground fault.
Check up serviceability of a condition and reliability of fixing of contact sockets of electroconducting on the control module ABS, the generator and the storage battery. Carry out appropriate reconditioning if necessary. If there are no violations of the quality of contacts, proceed to the next step of the test.
Switch off the ignition. Restore the original wiring connection. Clear the processor memory and repeat the procedure for reading diagnostic codes. If no change (in the direction of improvement) has occurred, replace the ABS control module/hydraulic modulator assembly. When new codes appear, go to the appropriate test. If the failure did not repeat, therefore, the malfunction was temporary, - once again make sure that all contact connections are securely fastened.
Violation of serviceability of functioning of a control system АТ (DTC 44)
Ignition OFF, and disconnect the two transmission control module (TCM) harness connectors. Also disconnect the electrical wiring from the ABS control module. Measure the resistance between terminal No. 3 of connector F49 and chassis ground. If the measurement is more than 1 MΩ, proceed to the next step of the test, otherwise, recondition the wiring between the TCM and the ABS control module.
Switch on the ignition and measure the voltage between ground and terminal No. 3 of connector F49. If the measurement is less than 1V, proceed to the next step of the test, otherwise perform the necessary reconditioning of the wiring between the TCM and the ABS control module.
Measure the voltage between ground and terminals No. 3 and 31 of connector F49. If the measurement result is within the range of 10 ÷ 15 V, proceed to the next step of the test, otherwise check the condition of the wiring in the area between the ABS control module and the TCM. Make necessary repairs.
Check up a condition and reliability of fixing of contact sockets of modules of management ABS and АТ. If necessary, clean the terminals and proceed to the next step of the test.
Switch off the ignition. Restore the original wiring connection. Clear the processor memory and repeat the procedure for reading diagnostic codes. If no change (in the direction of improvement) has occurred, replace the ABS control module/hydraulic modulator assembly. When new codes appear, go to the appropriate test. If the failure did not repeat, therefore, the malfunction was temporary, - once again make sure that all contact connections are securely fastened.
Valve Relay Malfunction (DTC 51)
Switch off the ignition and disconnect the electrical wiring from the ABS control unit. Start the engine at idle and measure the voltage between terminals No. 1 and 24 of connector F49 of the ABS control module and chassis ground. If the measurement result is within the range of 10 ÷ 15 V, proceed to the next step of the test, otherwise check the condition of the wiring between the ABS control unit and the battery. Make necessary repairs.
Measure the resistance between terminals No. 23 (+) and 24 (-) of the control module connector. If the measurement result is more than 1 MΩ, proceed to the next step of the test, otherwise replace the control unit.
Check up serviceability of a condition and reliability of fixing of contact sockets of electroconducting on the control module ABS, the generator and the storage battery. Carry out appropriate reconditioning if necessary. If there is no violation of the quality of contacts, proceed to the next step of the test.
Switch off the ignition. Restore the original wiring connection. Clear the processor memory and repeat the procedure for reading diagnostic codes. If no change (in the direction of improvement) has occurred, replace the ABS control module/hydraulic modulator assembly. When new codes appear, go to the appropriate test. If the failure did not repeat, therefore, the malfunction was temporary, - once again make sure that all contact connections are securely fastened.
Malfunction of the drive motor / its relay (DTC 52)
Switch off the ignition. Disconnect the wiring from the ABS control module, then turn the ignition key back to the ON position and measure the voltage between the control module connector F49 terminal No. 25 and chassis ground. If the measurement result does not go beyond the range of 10 ÷ 15 V, proceed to the next step of the test, otherwise, repair the electrical wiring in the area between the battery and the control module / hydromodulator. Check the SBF fuse holder.
Switch off the ignition and measure the resistance between ground and terminal No. 26 of connector F49. If the measurement result is less than 0.5 ohm, proceed to the next step of the test, otherwise, repair the ground circuit of the control unit.
Start the engine at idle and measure the voltage between terminal No. 1 of connector F49 and chassis ground. If the measurement result is within the range of 10 ÷ 15 V, proceed to the next step of the test, otherwise check the condition of the wiring in the areas between the battery, the ignition switch and the ABS control module. Make necessary repairs.
Switch off the ignition and measure the resistance between ground and terminal No. 23 of connector F49. If the measurement result is less than 0.5 ohm, proceed to the next step of the test, otherwise, eliminate the cause of the ground fault.
In the course of checking the sequence of operation of the hydraulic modulator valves (see Section Checking the sequence of operation of the ABS hydraulic modulator valves) by ear, check the correct operation of the electric motor. If the motor rotates properly, proceed to the next step of the test, otherwise replace the ABS modulator/control unit assembly.
Check the serviceability of the condition and the reliability of the fixation of the electrical wiring connectors on the ABS control module / hydraulic modulator assembly, generator and battery. Carry out appropriate reconditioning if necessary. If there are no violations of the quality of contacts, proceed to the next step of the test.
Switch off the ignition. Restore the original wiring connection. Clear the processor memory and repeat the procedure for reading diagnostic codes. If no change (in the direction of improvement) has occurred, replace the ABS control module/hydraulic modulator assembly. When new codes appear, go to the appropriate test. If the failure did not repeat, therefore, the malfunction was temporary, - once again make sure that all contact connections are securely fastened.
Violation of serviceability of functioning of the gauge-switch of stoplights (DTC 54)
Failure of the sensor-switch of brake lights leads to a malfunction of the ABS.
Check the brake lights for proper operation when the foot brake pedal is depressed. If everything is in order, proceed to the next step of the test, otherwise check the condition of the lamps and wiring of the brake light circuit.
Switch off the ignition. Disconnect the wiring from the ABS control module. Depress the foot brake pedal and measure the voltage between ABS control module connector F49 terminal No. 2 and chassis ground. If the measurement result is within the range of 10 ÷ 15 V, proceed to the next step of the test, otherwise check the condition of the wiring in the area between the brake light switch and the ABS control module. Make necessary repairs.
Check the condition and reliability of the fixation of the contact connectors of the sensor-switch and the control unit. Make appropriate corrections if necessary. If the contacts are in order, proceed to the next step of the test.
G-Sensor Output Malfunction (DTC 56)
Check the marking of the assembly of the ABS control module / hydraulic modulator, - the code is applied to the surface of the block between the fittings for connecting the hydraulic lines and for models (see Specifications). If the marking corresponds to the configuration of your car, proceed to the next step of the test, otherwise replace the ABS control module / hydraulic modulator assembly.
|
Switch off the ignition. Remove the central console (see the Head Body). Unscrew the G-sensor without disconnecting the electrical wiring from it. Turn the ignition key back to the ON position and measure the voltage between terminals No. 1 (+) and 3 (-) on the outside of the sensor connector R70. If the measurement result is within the range of 4.75 ÷ 5.25 V, proceed to the next step of the test, otherwise check the condition of the wiring in the area between the sensor and the ABS control module. Make necessary repairs. |
Switch off the ignition. Disconnect the wiring from the ABS control module and measure the resistance between terminals No. 6 and 28 of connector F49 of the control module. If the measurement result is within the range of 4.3 ÷ 4.9 kOhm, proceed to the next step of the test, otherwise, perform the necessary reconditioning of the wiring in the area between the sensor and the ABS control module.
Disconnect the electrical wiring from the G-sensor. Measure the resistance between terminal No. 6 of connector F49 and chassis ground. If the measurement result is more than 1 MΩ, proceed to the next step of the test, otherwise, make the necessary reconditioning of the wiring in the area between the sensor and the ABS control module.
Measure the voltage between terminal No. 6 of connector F49 and chassis ground. If the measurement result is less than 1 V, proceed to the next step of the test, otherwise, make the necessary reconditioning of the wiring in the area between the sensor and the ABS control module.
Repeat the last check with the ignition on. If the measurement result is less than 1 V, proceed to the next step of the test, otherwise, make the necessary reconditioning of the wiring in the area between the sensor and the ABS module.
Measure the resistance between ground and terminal No. 28 of connector F49. If the measurement result is more than 1 MΩ, proceed to the next step of the test, otherwise, make the necessary reconditioning of the wiring in the area between the sensor and the ABS control module. If wiring is OK, replace control module/hydraulic modulator assembly.
Turn off the ignition and, without disconnecting the wiring, unbolt the G-sensor. Check up reliability of fixing of contact sockets of the sensor and control module ABS. Turn on the ignition and measure the voltage between terminals No. 2 (+) and No. 3 (-) of the sensor connector R70. If the measurement result is within the range of 2.1 ÷ 2.4 V, proceed to the next step of the test, otherwise replace the sensor.
Tilt the transducer 90° forward and repeat the above test. If the measurement result is within the range of 3.7 ÷ 4.1 V, proceed to the next step of the test, otherwise replace the sensor.
Tilt the transducer 90° backwards and repeat the test again. If the measurement result is within the range of 0.5 ÷ 0.9 V, proceed to the next step of the test, otherwise replace the sensor.
Switch off the ignition. Check up a condition and reliability of fixing of contact sockets of the G-sensor and module ABS. Carry out appropriate reconditioning if necessary. If the contact connections are in order, proceed to the next step of the test.
Restore the original wiring connection. Clear the processor memory and repeat the procedure for reading diagnostic codes. If no change (in the direction of improvement) has occurred, replace the ABS control module/hydraulic modulator assembly. When new codes appear, go to the appropriate test. If the failure did not repeat, therefore, the malfunction was temporary, - once again make sure that all contact connections are securely fastened.
Checking the I/O Signals of the ABS Control Module
The map of the location of the contact terminals in the connector of the control module / hydraulic modulator and the wiring diagram of the ABS components are shown in the illustrations.
ABS Wiring Diagram
1 - Assembling the control module / ABS hydraulic modulator |
13 - Right rear wheel outlet solenoid valve |
Map of the location of the contact terminals in the connector of the ABS control module
The waveform taken from the individual terminals of the ABS sensors is shown in resist. illustrations. The list of signals is given in the table.
Reading trouble codes (DTC) ABS
For a list of ABS DTCs, refer to Specifications on this chapter.
Reading DTCs using SSM
Get the SSM reader ready for use.
Connect to SSM diagnostic cable and refill the cartridge.
Connect the SSM diagnostic cable to the DLC connector located on the left under the vehicle's instrument panel.
Turn the ignition key to the ON position (do not start the engine) and power on the SSM.
In the Main Menu of the reader screen, select the section (Each System Check) and press the YES key.
In the "System Selection Menu" field of the screen, select the subsection (Brake Control System), confirm the selection by pressing the YES key.
After displaying information about ABS type press the YES key again.
In the "ABS Diagnosis" field of the screen, select the item (Diagnostic Code(s) Display) and confirm the selection by pressing the YES key.
Select (Current Diagnostic Code(s)) or (History Diagnostic Code(s)) in the "Diagnostic Code(s) Display" field of the screen, press the YES key.
Reading current data
Enter the menu subsection (Brake Control System), wait for the ABS type message to appear on the screen and press the YES key.
In the "Brake Control Diagnosis" field of the screen, select the item (Current Data Display & Save) and confirm the selection by pressing the YES key.
In the Data Select Menu field, select (Data Display) and press YES.
Use the scroll buttons to move through the list displayed on the screen and select the data you are interested in. The list of output data is given in the table below.
|
monitor screen |
Output type |
Units |
|
Speed corresponding to the rotational speed of the right front wheel |
Right front wheel sensor data |
km/h or miles/h |
|
Speed corresponding to the rotational speed of the left front wheel |
Data provided by the left front wheel sensor |
km/h or miles/h |
|
Speed corresponding to the speed of the right rear wheel |
Right rear wheel sensor data |
km/h or miles/h |
|
Speed corresponding to the rotational speed of the left rear wheel |
Data provided by the left rear wheel sensor |
km/h or miles/h |
|
Brake light switch |
Status of the sensor-switch |
On or Off |
|
Brake light switch |
Brake light switch voltage output | |
|
G-sensor input |
G-sensor signal voltage (vehicle acceleration data) | |
|
Valve relay signal |
Valve relay signal |
On on or off |
|
Motor relay signal |
Motor relay signal |
On on or off |
|
ABS signal to TCM |
The signal issued by the ABS control module to the TCM AT |
On on or off |
|
ABS warning lamp |
Data output about the operation of the ABS warning lamp |
On on or off |
|
Motor Relay Monitoring |
Output of motor relay activation data |
high or low |
|
Valve relay monitoring |
Valve relay activation data output |
On on or off |
|
CCM signal |
ABS function signal from the ABS control module to the AT TCM |
On on or off |
Reading DTCs without using SSM
Remove the diagnostic connector located next to the driver's seat heater unit.
Turn off the ignition and connect the diagnostic terminal to terminal No. 8 of the connector.
Turn the ignition on, the ABS warning lamp will go into diagnostic mode and start flashing the fault codes (DTCs) stored in the processor memory.
The test start code (11) is always displayed first, then all other codes are output in turn, starting with the last one. After the last code is displayed, the cycle repeats for 3 minutes. Examples of code output are shown in the illustration. If there are no codes stored in the memory, the control lamp will display only the start code (11).
Deleting codes from processor memory
Using SSM
From the Main Menu of the SSM reader, select (2. Each System Check) and press the YES key.
In the System Select Menu, select (Brake System), press YES, wait until the ABS type information is displayed, then press YES again.
In the "Brake Control Diagnosis" field of the screen, select the item (Clear Memory) and confirm the selection by pressing the YES key.
After the reader displays the messages “Done” and “Turn ignition OFF”, power off the SSM and turn off the ignition.
Without SSM
Within approximately 12 seconds, repeat the procedure for connecting / disconnecting the terminal three times with the duration of each phase (On and Off) of at least 0.2 s.
Successful completion of the memory clearing is confirmed by the flashing of code 11 by the control lamp.
Required entry: This article can be considered both as a "guide to action", and as just an attempt to explain the principles of work ABS systems for all those who have not yet encountered or have just begun to study this system. Do not look here for answers to all the questions that arise, because, as practice shows, such "nuances" always arise, for the solution of which it is required not to blindly follow the instructions or the advice given here, but to apply " technical trick" and take this article only as a basis or as a "push to reflection."
Vladimir Petrovich
Yuzhno-Sakhalinsk
... The client was pale and talkative. The right wing of his "swallow" was crumpled, which is why his Lexus, which previously had a "haughty" look, now looked like a battered mongrel...
The client spoke a lot and quickly, and from his conversation it gradually became clear that “he walked as usual, in the left lane and no more than 80 kilometers. then slow down ... and then the car started to go away. It went away, despite the existing ABS system. And, in order not to hurt some other, sparkling varnished car, I had to "grind" to the curb.
We remember this client. Firstly, a fairly fresh and very well-groomed car, and secondly, he did not come to us for repairs, but in order for us to simply check - "how the" engine "works" and whether everything is fine with it.
... We begin to check the performance of the ABS system. I must say that from practice we have deduced the following for ourselves: malfunctions in the ABS system can be "static" and "dynamic".
"Static" - these are those whose cause constantly "sits" in the memory of the on-board computer. For example, a broken wire to the sensor, a jammed electric motor of the hydraulic modulator, a faulty sensor itself or sensors ("sensors" - this is extremely rare, usually one sensor fails, and what would immediately fail several - it was only once ...) .
"Dynamic" malfunctions are such malfunctions that are detected only when driving, when the "decision speed" is reached - 10 km / h. It is this speed that was adopted by the Japanese developers of ABS systems and "laid into the memory" of the ABS computer as the speed at which the computer "needs to decide" how well and "correctly" the ABS system works and whether it will ensure safe movement in the future.
The ABS system itself works as follows: when the ignition is turned on, the ABS system computer “wakes up” and begins to “interrogate” the speed sensors, the modulator, all circuits and itself for serviceability and “readiness for work”. At this time, the instrument panel lights up ABS bulb. All this takes 1-2 seconds, and if everything is fine, then after the "interrogation" the ABS computer "calms down" and turns off the light on the panel. If somewhere in the ABS system a “static” malfunction is detected in the form of a broken wire, a faulty sensor, and so on, the ABS light on the instrument panel continues to burn and “tells” us that “it is impossible to start moving, a failure has occurred in the ABS system .Understand."
If the ABS light comes on after reaching the "decision speed" - this is already a "dynamic" malfunction and it may occur, for example, due to the fact that some wheel sensor incorrectly reads "motion information" or does not "read" it at all . Here, the reason may be that, for example, the air gap (Air Gap) between the speed sensor and the gear on the hub is greater than the permissible limits. Or itself gear has chips on the hub. In any case, it is necessary to carry out the procedure of self-diagnosis and "determine".
To do this, Toyota, as well as other brands of cars, has a so-called "self-diagnosis block".
Let's open it. On the inside covers are painted pins. Let's find "Tc - E1". However, let's not rush, because if we immediately bridge these contacts, we may not get the fault code we need. We also need to find the contacts "Wa - Wb", which are closed with a short pin (Short Pin)
This pin must be pulled out for self-diagnosis of the ABS system. Now you can close the contacts Tc - E1. The following is a breakdown of the Toyota ABS trouble codes (however, it should not be assumed that the following trouble codes are suitable for ALL Toyota vehicles):
| 11 | open circuit relay e / m valve |
| 12 | short circuit in the relay circuit of the valve |
| 13 | break in the electric pump relay circuit |
| 14 | short circuit in the electric pump relay circuit |
| 15 | short circuit or open circuit TRAC solenoid relay |
| 21 | open or short circuit in the right front wheel solenoid |
| 22 | open or short circuit in the left front wheel solenoid |
| 23 | open or short circuit in the right rear wheel solenoid |
| 24 | open or short circuit in the left rear wheel solenoid |
| 31 | error in the signal of the speed sensor of the front right wheel |
| 32 | error in the left front wheel speed sensor signal |
| 33 | error in the right rear wheel speed sensor signal |
| 34 | error in the left rear wheel speed sensor signal |
| 35 | break in the speed sensor of the front left / rear right wheels |
| 36 | break in the speed sensor of the front right / rear left wheels |
| 37 | rear axle hubs defective |
| 41 | battery voltage less than 9.5 V or more than 16.2 V |
| 51 | hydraulic control unit pump motor blocked or pump motor circuit interrupted |
| 52 | Blocked hydraulic control unit pump motor |
- Did you do anything with the "hodovka"?
-Changed pads...
We have no questions, as they say. While the client is swearing and threatening to "tear off his head" to that "specialist", let's say that even replacing pads or something else on cars with an ABS system must be trusted by a person who has at least some idea about the structure and operation of the ABS system. What happened in this case?
It's simple: either that "specialist" was in a hurry, or something else, but he did not fix the tourniquet on the rack. Further, events developed as follows - Winter, snow, somewhere the roads are wet, with puddles, the car is driving and snow is slowly sticking to the harness hanging near the wheel itself, gradually turning into ice. At first a little, and then more and more, and finally there comes a moment when the weight of the adhering ice exceeds the weight of the tourniquet itself, and on every bump or bump in the road, the tourniquet begins to twitch and dangle strongly. That's what mounts are for...
So what to do? Remove and replace the sensor? Let's pause. As my old friend Leva Kiperman said: "There is one way ...".
Before you suffer and remove the speed sensor (and removing it is a rather lengthy procedure, because, as a rule, speed sensors so "well" turn sour in the "body" of the hub that you have to pull it out literally by a millimeter) - let's first check and try to establish a place cliff. We know the resistance of the speed sensor - 970 ohms (plus or minus), so we will proceed from this.
First, disconnect the connector and "sit down" on the contacts with a multimeter. Alas, nothing. Then we go further and begin to check the resistance on these two wires every 10 - 15 centimeters. It is highly desirable that the probes be sharply sharpened in order to be able to pierce the wire. ... and somewhere in the middle of the harness we found a break. It's good that in this "convenient" place, and not the sensor itself - then it would have been difficult.
As you can see, "by itself" the ABS system almost never fails.
There will always be a "specialist" who will "help" her. And no matter what happens - here you are little advice:
"Cool" you have a car or "ordinary" - it does not matter. Find one master (workshop) in your city, where people are "thinking", and not just "making money". Understand. And let them "lead" your car throughout its "life". And even if this master (workshop) is highly specialized (which is very good!) And they do not perform some work, then before repairing something "on the side" - consult.
Real, conscientious masters will not advise you bad.
And finally, a few tips and tricks.
First, - "how to remove the fault code?".
In books they write about this "many and different things", but you can do it easier, faster, and more correctly: after eliminating the malfunction, remove the "negative" battery terminal for 30-40 seconds, and then put it back on. Well, if for some reason it didn’t work out, then in another way:
- tighten the parking brake;
- jumper contacts Tc - E1
- delete fault codes according to the scheme: press the brake pedal at least 8 times, each time holding the pedal for at least 3 seconds;
- check if the ABC light shows any code or not.
However, it should be remembered that this method is not applicable to all Toyota models.
You can "diagnose" your car yourself if you carefully read the following:
If sometimes the ABS light comes on when braking, then check your tires.
Isn't she "bald"? Because at the moment the brakes are released, the "front" of the car goes up a little, and at the same time, such a situation as the operation of a "malfunction" of the ABS due to loss of traction is possible.
If the light began to burn after carrying out any work on the running gear - check the connector connections ("guys" could simply forget to connect them), the resistance of the sensors - "running gears" are usually repaired with mounts, and they tend to slip off and at the same time that - to tear or pull. Possible breakage of the "teeth" when replacing the hub. It's easy to check: remove the sensor, insert something plastic and flexible into the hole and rotate the wheel. And listen. If there is an oscilloscope, then everything will be visible on the screen: where there is no tooth or it is broken, there will be a "failure" in the sequence of output pulses. And on Toyota, with the hub removed, everything is visible from the inside.
If the ABS light comes on "sometimes", and it is useless to look for some kind of cyclicity or pattern in this, because it simply does not exist, then you should check the connections, chips, how the relays sit in the sockets, i.e. contact quality. If everything is fine, and the light starts to light up when a certain speed is reached, then check first of all the cleanliness gear wheels in the hubs. Jack, a clean brush in gasoline and rotate, rotate ...
If again everything is fine, and the light comes on, check the voltage. In the ABS block there is such a transistor B 1015, which stabilizes the voltage (green, in a plastic case), and so, there should be 4.8-5.1 volts on the collector. "Brains" will not work when the voltage of the on-board network is reduced.
The health of the ABS system also largely depends on how correctly and fully the entire system is filled with hydraulic fluid. Because if the system is at least a little “airy”, then this is fraught with unpredictable consequences during emergency braking at high speed, especially on slippery roads.
Below are a few symptoms, the appearance of which can, with a certain degree of probability, speak of the "airiness" of the system, i.e. about the need to remove air from it.
At speeds over 40 km/h and heavy braking:
The brake pedal perceptibly "beats" in the foot with the same frequency (several times per second);
Feeling as if the front of the car "pounds";
Hands on the steering wheel feel bumps and the steering wheel twitches from side to side;
The car does not slow down "exactly", but with a skid in one direction.
If you brake at a lower speed and not so sharply, then the foot will still feel the impact of the brake pedal. All this can be explained in this way: when air enters the system, the hydraulic fluid is no longer "practically incompressible", since it is "diluted" with air bubbles, which give the effect of a "failure" in the pressure of one or another hydraulic branch. During a "failure" on some wheel - it is blocked by pads, while the other wheel works without a "failure".
The system is already unbalanced, but the ECU is trying to work according to the established algorithm, which does not provide for such an incomprehensible situation as the presence of air bubbles in the fluid, which “fail” the system as they please ... All these brake pedal strikes in the leg - and there is an attempt to "brain "Deal with emergency situations.
We begin to pump the system from the far wheel from the hydraulic modulator. Everything is as usual - we remove the rubber cap from the valve, connect a transparent hose to it, lower it into a container with hydraulic fluid and unscrew the valve (key 10).
Thereafter:
- Turn on the ignition;
- We press the brake pedal all the way (second person);
- We look at the end of the hose - air bubbles come from there;
- We turn off the ignition.
When you press the brake pedal hard and high speed- the leg practically does not feel the pulsation of the brake pedal.
The car brakes smoothly and without skidding.
It should be noted that the causes of the described situation may be brake disc wear and faulty shock absorbers.
And, of course, try at every opportunity (when replacing, for example, brake pads) to do preventive maintenance of sensors, i.e. cleaning them from dirt and metal debris, which "strives" to be magnetized.
