In principle, ESC and TCS controls are prohibited in case of ABS failure.
2.
When ESC or TCS fails, only the failed system control is prohibited.
3.
However, when the solenoid valve relay should be turned off in case of ESC failure, refer to the ABS fail-safe.
4.
Information on ABS fail-safe is identical to the fail-safe in systems where ESC is not installed.
Memory of Fail Code
1.
It keeps the code as far as the backup lamp power is connected. (O)
2.
It keeps the code as far as the HCU power is on. (X)
Failure Checkup
1.
Initial checkup is performed immediately after the HECU power on.
2.
Valve relay checkup is performed immediately after the IG2 ON.
3.
It executes the checkup all the time while the IG2 power is on.
Countermeasures in Case of Failure
1.
Shut the system down, perform the following actions, and wait for HECU to power OFF.
2.
Turn the valve relay off.
3.
Stop the control during the operation and do not execute any until the normal condition recovers.
Warning Lamp ON
1.
ESC warning lamp turns on for 3 sec. after IGN ON.
2.
ESC function lamp blinks when ESC Act.
3.
If ESC fail occured, ESC warning turns ON.
4.
ESC OFF lamp turns on in the following cases:
–
ESC Switch OFF
–
3 sec. after IGN ON
Standard Flow of Diagnostic Troubleshooting
Notes With Regard To Diagnosis
The phenomena listed in the following table are not abnormal.
Condition
Explanation
System check sound
When starting the engine, a thudding sound can sometimes be heard coming from inside the engine compartment. This is because the system operation check is being performed.
ABS operation sound
1)
Sound of the motor inside the ABS hydraulic unit operation (whine).
2)
Sound is generated along with vibration of the brake pedal (scraping).
3)
When ABS operates, sound is generated from the vehicle chassis due to
repeated brake application and release
(Thump : suspension; squeak: tires)
ABS operation (Long braking distance)
On
snow-covered or gravel road surface, etc., the braking distance for
vehicles with ABS can sometimes be longer than those without ABS.
Accordingly, advise customers to drive safely on such road conditions by
reducing the vehicle speed.
Diagnosis detection conditions can vary depending on the diagnostic code. checking
the trouble symptom after the diagnostic code has been erased, ensure
that the requirements listed in "Comment" are met.
ABS Check Sheet
Problem Symptoms Table
Symptom
Suspect Area
ABS does not operate.
Replace the HECU only when the problem persists even though conditions 1-4 are satisfied.
1)
Check the DTC reconfirming that normal code is output.
2)
Check power source circuit.
3)
Check speed sensor circuit.
4)
Check hydraulic circuit for leakage.
ABS does not operate intermittently.
Replace the ABS actuator assembly onlt when the problem persists even though conditions 1-4 are satisfied.
1)
Check the DTC reconfirming that normal code is output.
2)
Check wheel speed sensor circuit.
3)
Check stop lamp switch circuit.
4)
Check hydraulic circuit for leakage.
Communication with GDS is not possible. (Communication with any system is not possible)
1)
Power source circuit
2)
CAN line
Communication with GDS is not possible. (Communication with ABS only is not possible)
1)
Power source circuit
2)
CAN line
3)
HECU
When ignition key is turned ON (engine OFF), the ABS warning lamp does not light up.
1)
ABS warning lamp circuit
2)
HECU
Even after the engine has started, the ABS warning lamp remains ON.
1)
ABS warning lamp circuit
2)
HECU
During ABS operation, the brake pedal may vibrate or may not
be able to be depressed. Such phenomena are due to intermittent changes
in hydraulic pressure inside the brake line to prevent the wheels from
locking and is not an abnormality.
Detecting condition
Trouble Symptoms
Possible Cause
Brake
operation varies depending on driving conditions and road surface
conditions, so diagnosis can be difficult. However if a normal DTC is
displayed, check the following probable cause. When the problem is still
occurring, replace the ESC control module.
–
Faulty power source circuit
–
Faulty wheel speed sensor circuit
–
Faulty hydraulic circuit for leakage
–
Faulty HECU
Inspection procedures
DTC Inspection
1.
Connect the GDS with the data link connector and turn the ignition switch ON.
2.
Verify that the DTC code is set.
3.
Does the DTC code set?
â–¶ Check the power source circuit.
â–¶ Erase the DTC and recheck using GDS.
Check the power source circuit
1.
Disconnect the connector from the ESC control module.
2.
Turn the ignition switch ON, and measure the voltage between
terminal 29 of the ESC control module harness side connector and body
ground.
Specification: approximately B+
3.
Is the voltage within specification?
â–¶ Check the ground circuit.
â–¶
Check the harness or connector between the fuse (10A) in the engine
compartment junction block and the ESC control module. Repair if
necessary.
Check the ground circuit
1.
Disconnect the connector from the ESC control module.
2.
Check for continuity between terminals 13, 38 of the ESC control module harness side connector and ground point.
3.
Is there continuity?
â–¶ Check the wheel speed sensor circuit.
â–¶ Repair an open in the wire and ground point.
Check the wheel speed sensor circuit
1.
Refer to the DTC troubleshooting procedures.
2.
Is it normal?
â–¶ Check the hydraulic circuit for leakage.
â–¶ Repair or replace the wheel speed sensor.
Check the hydraulic circuit for leakage
1.
Refer to the hydraulic lines.
2.
Inspect leakage of the hydraulic lines.
3.
Is it normal?
â–¶ The problem is still occurring, replace the ESC control module.
â–¶ Repair the hydraulic lines for leakage.
Detecting condition
Trouble Symptoms
Possible Cause
Brake
operation varies depending on driving conditions and road surface
conditions, so diagnosis can be difficult. However if a normal DTC is
displayed, check the following probable cause. When the problem is still
occurring, replace the ESC control module.
–
Faulty power source circuit
–
Faulty wheel speed sensor circuit
–
Faulty hydraulic circuit for leakage
–
Faulty HECU
Inspection procedures
DTC Inspection
1.
Connect the GDS with the data link connector and turn the ignition switch ON.
2.
Verify that the DTC code is output.
3.
Is the DTC code output?
â–¶ Check the wheel speed sensor circuit.
â–¶ Erase the DTC and recheck using GDS.
Check the wheel speed sensor circuit
1.
Refer to the DTC troubleshooting procedures.
2.
Is it normal?
â–¶ Check the stop lamp switch circuit.
â–¶ Repair or replace the wheel speed sensor.
Check the stop lamp switch circuit
1.
Check that stop lamp lights up when brake pedal is depressed and turns off when brake pedal is released.
2.
Measure the voltage between terminal 23 of the ESC control
module harness side connector and body ground when brake pedal is
depressed.
Specification : approximately B+
3.
Is the voltage within specification?
â–¶ Check the hydraulic circuit for leakage.
â–¶ Repair the stop lamp switch. Repair an open in the wire between the ESC control module and the stop lamp switch.
Check the hydraulic circuit for leakage
1.
Refer to the hydraulic lines.
2.
Inspection leakage of the hydraulic lines.
3.
Is it normal?
â–¶ The problem is still occurring, replace the ESC control module.
â–¶ Repair the hydraulic lines for leakage.
Detecting condition
Trouble Symptoms
Possible Cause
Possible defect in the power supply system (including ground) for the diagnosis line.
–
An open in the wire
–
Poor ground
–
Faulty power source circuit
Inspection procedures
Check The Power Supply Circuit For The Diagnosis
1.
Measure the voltage between terminal 16 of the data link connector and body ground.
Specification : approximately B+
2.
Is voltage within specification?
â–¶ Check the ground circuit for the diagnosis.
â–¶ Repair an open in the wire. Check and replace fuse from the engine compartment junction block.
Check the ground circuit for the diagnosis
1.
Check for continuity between terminal 4 of the data link connector and body ground.
2.
Is there continuity?
â–¶ Repair an open in the wire between terminal 4 of the data link connector and ground point.
Detecting condition
Trouble Symptoms
Possible Cause
When
communication with GDS is not possible, the cause may be probably an
open in the HECU power circuit or an open in the diagnosis output
circuit.
–
An open in the wire
–
Faulty HECU
–
Faulty power source circuit
Inspection procedures
Check for Continuity in the CAN Line
1.
Disconnect the connector from the ESC control module.
2.
Check for continuity between terminals 26, 14 of the ESC control module connector and 3, 11 of the data link connector.
3.
Is there continuity?
â–¶ Check the power source of ESC control module.
â–¶ Repair an open in the wire.
Check the power source of ESC control module
1.
Disconnect the connector from the ESC control module.
2.
Turn the ignition switch ON, and measure the voltage between
terminal 29 of the ESC control module harness side connector and body
ground.
Specification : approximately B+
3.
Is voltage within specification?
â–¶ Check for poor ground.
â–¶
Check the harness or connector between the fuse (10A) in the engine
compartment junction block and the ESC control module. Repair if
necessary.
Check for poor ground
1.
Check for continuity between terminal 4 of the data link connector and ground point.
â–¶ Replace the ESC control module and recheck.
â–¶ Repair an open in the wire or poor ground
Detecting condition
Trouble Symptoms
Possible Cause
When current flows into the HECU, the ABS warning lamp changes from ON
to OFF as the initial check. Therefore, if the lamp does not light up,
the cause may be with an open in the lamp power supply circuit, a blown
bulb, an open in both circuits between the ABS warning lamp and the
HECU, or faulty HECU.
–
Faulty ABS warning lamp bulb
–
Blown fuse is related to ABS in the engine compartment junction block
–
Faulty ABS warning lamp module
–
Faulty HECU
Inspection procedures
Problem verification
1.
Disconnect the connector from the ESC control module and turn the ignition switch ON.
2.
Does the ABS warning lamp light up?
â–¶ Inspect again after replacing the ESC HECU.
â–¶ Check the power source for the ABS warning lamp.
Check the power source for the ABS warning lamp
1.
Disconnect the instrument cluster connector (M08) and turn the ignition switch ON.
2.
Measure the voltage between terminal (M08) 39 of the cluster harness side connector and body ground.
Specification : approximately B+
3.
Is voltage within specification?
â–¶ Check the CAN circuit resistance for ABS warning lamp.
â–¶ Check for blown fuse.
Check the CAN circuit resistance for ABS warning lamp
1.
Disconnect the instrument cluster connector (M08) and turn the ignition switch OFF.
2.
Measure the resistance between terminal (M08) 32 and 33 of the cluster harness side connector.
Specification : 60Ω
3.
Is resistance within specification?
â–¶ Repair ABS warning lamp bulb or instrument cluster assembly.
â–¶ Check the CAN circuit wiring for ABS warning lamp.
Check the CAN circuit wiring for ABS warning lamp
1.
Disconnect the instrument cluster connector (M08) and ESC HECU connector, and then turn the ignition switch OFF.
2.
Check for continuity between terminal (M08) 32 of the cluster harness side connector and terminal 26 of ESC HECU harness side.
Check for continuity between terminal (M08) 33 of the cluster harness side connector and terminal 14 of ESC HECU harness side.
Specification : Below 1Ω
3.
Is resistance within specification?
â–¶ Repair short of wiring between terminal 26, 14 of ESC HECU harness connector and ABS warning lamp module.
â–¶ Repair open of wiring between terminal 26, 14 of ESC HECU harness connector and ABS warning lamp module.
Detecting condition
Trouble Symptoms
Possible Cause
When
the HECU detects trouble, it lights the ABS warning lamp while
prohibiting ABS control at the same time. In this case, the HECU records
a DTC in memory. If the ABS warning lamp remains ON even though normal
code is output, the cause may probably be with an open or short in the
ABS warning lamp circuit.
–
An open in the wire
–
Faulty instrument cluster assembly
–
Faulty ABS warning lamp module
–
Faulty HECU
Inspection procedures
Check DTC Output
1.
Connect the GDS to the 16P data link connector located behind the driver''s side kick panel.
2.
Check the DTC output using GDS.
3.
Is DTC output?
â–¶ Perform the DTC troubleshooting procedure (Refer to DTC troubleshooting).
â–¶ Check the CAN circuit resistance for ABS warning lamp.
Check the CAN circuit resistance for ABS warning lamp
1.
Disconnect the instrument cluster connector (M08) and turn the ignition switch OFF.
2.
Measure the resistance between terminal (M08) 32 and 33 of the cluster harness side connector.
Specification : 60Ω
3.
Is resistance within specification?
â–¶ Repair ABS warning lamp bulb or instrument cluster assembly.
â–¶ Check the CAN circuit wiring for ABS warning lamp.
Check the CAN circuit wiring for ABS warning lamp
1.
Disconnect the instrument cluster connector (M08) and ESC HECU connector, and then turn the ignition switch OFF.
2.
Check for continuity between terminal (M08) 32 of the cluster harness side connector and terminal 26 of ESC HECU harness side.
Check for continuity between terminal (M08) 33 of the cluster harness side connector and terminal 14 of ESC HECU harness side.
Specification : Below 1Ω
3.
Is resistance within specification?
â–¶ Repair short of wiring between terminal 26, 14 of ESC HECU harness connector and ABS warning lamp module.
â–¶ Repair open of wiring between terminal 26, 14 of ESC HECU harness connector and ABS warning lamp module.
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