Diagnostics of ABS failures
Wiring diagram for ABS warning lampABS 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 make sure the parking brake is fully released and the brake system is working 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 module of management 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 reason for failures in the operation of the ABS warning lamp may be an open or short circuit in its electrical wiring 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. Make necessary repairs.
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.
Turn 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 connector of the ABS control module / hydraulic modulator 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.
Run the engine to idle and check for voltage between the B (+) terminal on the back 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 cannot 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 go beyond 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 section of the circuit between the sensor and the control module / ABS 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 step of the test, 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 up reliability of a tightening of bolts of fastening of sensors ABS (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 cannot 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 greater 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 test step, otherwise, perform the necessary reconditioning of the wiring in the area 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 is within the range of 10 ÷ 15 V, proceed to the next step of the test, otherwise, recondition the 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 assembly of the ABS control module / hydraulic modulator, 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 sensor-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 on 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.
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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 kΩ, 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 the diagnostic cable to the SSM 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 the ABS type information, 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.
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 car body 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 ABS repair involves troubleshooting a system that provides a quick deceleration during emergency braking. The abbreviation is formed from the first letters of the English term: Anti-lock Brake System. At the appropriate level, repair of Toyota ABS will be carried out by the masters of the Autopilot service. The Toyota Technical Center specializes in servicing vehicles manufactured in Japan. Specialists who thoroughly know the structure of models produced in different years are involved. When repairing the Toyota ABS unit, original components are installed instead of worn out elements.
Emergency braking system: how to restore its performance?
Toyota ABS repair is started after a set of diagnostic measures. Studied in detail:
- Control block;
- sensors responding to speed changes;
- executive device.
Reasons to Repair Toyota ABS Unit
Toyota ABS repair is started if the system indicator is constantly on while driving. The wheels are blocked, but for this, pressing the pedal must be of great force. Repair of the Toyota ABS unit before the due date is performed when:
- penetration of moisture into the mechanism;
- operation of the vehicle in difficult weather conditions;
- damage to the device in contact with substances of an aggressive nature.
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.
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
