Troubleshooting

Fault Diagnosis

1. 1
   In principle, ESP and TCS control is prohibited when an ABS failure occurs.
2. 2
   If an ESP or TCS failure occurs, only the malfunctioning system control is prohibited.
3. 3
   However, when the solenoid valve relay must be turned off in the event of an ESP failure, refer to ABS fail-safe.
4. 4
   ABS fail-safe information is identical to the fail-safe for systems where ESP is not installed.
5. 5
   It stores the code as long as backup lamp power is connected. (O)
6. 6
   It stores the code as long as HCU power is on. (X)
7. 7
   The initial check is performed immediately after the HECU is powered on.
8. 8
   The valve relay check is performed immediately after IG2 is turned on.
9. 9
   It performs the check at all times while IG2 power is on.
10. 10
    Turn the system off, perform the following steps, and wait until the HECU is turned off.
11. 11
    Turn off the valve relay.
12. 12
    Stop control during operation and do not take any action until normal condition is restored.
13. 13
    The ESP warning lamp illuminates for 3 seconds after ignition ON.
14. 14
    The ESP function lamp flashes when ESP is active.
15. 15
    If an ESP failure occurs, the ESP warning lamp illuminates.
16. 16
    The ESP OFF lamp illuminates in the case of

    • ESP OFF
    • 3 seconds after ignition ON

    

DTC Memory
Troubleshooting Procedure
Fail-safe Measures
Warning Lamp ON
Standard Troubleshooting Flow
Diagnostic Notes
The phenomena listed in the following table are not abnormal.

Condition	Description
System Check Sound	A dull knocking noise may be heard from inside the engine compartment when the engine is started. This is caused by the system performing a check.
ABS Operation Sound	1 A motor sound (whining) can be heard inside the ABS hydraulic unit. 2 A grinding sound is generated together with brake pedal vibration. 3 When the ABS is operating, noise comes from the vehicle chassis due to repeated pressing and releasing of the brake pedal. (Thump: suspension; squeal: tires)
ABS Operation (Longer Stopping Distance)	On road surfaces such as snow-covered and gravel roads, the braking distance of vehicles equipped with ABS may sometimes be longer than that of other vehicles. Therefore, advise the customer to drive safely on such roads by reducing vehicle speed.

Inspection Method: With the ignition OFF, turn the ignition ON. If the ABS/brake warning lamp illuminates and goes off after 3 seconds, the warning lamp and ABS system are normal.

1. 1
   If the warning lamp does not illuminate when the ignition switch is turned to the ON position.

   1. Disconnect the ABS control module connector (located in the engine compartment).
   2. Turn the IGN to the ON position.
   3. If the ABS/brake warning lamp does not illuminate: the malfunction is in the warning lamp circuit. Check the instrument cluster and wiring.
   4. If the ABS/brake warning lamp illuminates and remains on:

   The warning lamp is normal and indicates a malfunction of the VDC system. Inspect the VDC system using GDS.
2. 2
   If the warning lamp does not illuminate after it is turned on when the IGN is turned to the ON position.

   1. Self-diagnosis using GDS.
   2. Record the DTC.
   3. Self-diagnosis after clearing the DTC.
   4. If the self-diagnosis result is normal after clearing the DTC: Turn the IGN to the OFF position, then to the ON position, and check that the warning lamp operates normally.
   5. If the self-diagnosis result continues to display the malfunction after clearing the DTC: Check the DTC according to the check sheet.
3. 3
   Even if the warning lamp and VDC system are normal, clear all stored DTCs using GDS (if there are no stored DTCs, record the DTC).

   When disconnecting or connecting all connectors, turn the IGN to the OFF position. During the road test, record on the inspection sheet when the warning lamp illuminates or each time the event occurs.

   

ABS Checklist / Symptom Table

Symptom	Suspect area
ABS does not operate.	Only if items 1–4 are normal and the problem still occurs, replace the HECU. 1 Check the DTC to confirm that a normal code is output. 2 Power supply circuit. 3 Speed sensor circuit. 4 Check the hydraulic circuit for leaks.
ABS does not operate intermittently.	Only if items 1–4 are normal and the problem still occurs, replace the ABS actuator assembly. 1 Check the DTC to confirm that a normal code is output. 2 Wheel speed sensor circuit. 3 Stop lamp switch circuit. 4 Check the hydraulic circuit for leaks.
Communication with GDS is not possible. (Communication with any system is not possible)	1 Power supply circuit 2 CAN line
Communication with GDS is not possible. (Communication with the ABS only is not possible)	1 Power supply circuit 2 CAN line 3 HECU
When the ignition key is turned to the ON position (engine off), the ABS warning lamp does not illuminate.	1 ABS warning lamp circuit 2 HECU
Even after starting the engine, the ABS warning lamp remains on.	1 ABS warning lamp circuit 2 HECU

During ABS operation, the brake pedal may vibrate or fail to depress. These phenomena are caused by periodic changes in hydraulic pressure in the brake line to prevent wheel lock and are not a malfunction. These phenomena are caused by periodic changes in hydraulic pressure inside the brake lines to prevent wheel lock and are not a malfunction.

Detection condition

Symptom Condition	Possible Cause
Brake operation depends on driving conditions and road surface conditions, so diagnosis may be difficult. However, if a normal DTC is displayed, check the following possible causes. If the problem still occurs, replace the ESP control module.	Faulty power supply circuit Faulty wheel speed sensor circuit Faulty hydraulic circuit due to leakage Faulty HECU

Inspection Procedures. Check DTC.

1. 1
   Connect the GDS to the data link connector and turn the ignition switch ON.
2. 2
   Make sure that a DTC is output.
3. 3
   Is a DTC output?

   	▶ Check the power supply circuit.
   	▶ Clear the DTC and recheck using GDS.

4. 4
   Disconnect the connector from the ESP control module.
5. 5
   Turn the ignition on, and measure the voltage between terminal 29 of the ESP control module harness-side connector and body ground.

   Specification: Approximately B+

   Is the voltage within specification?

   	▶ Check the ground circuit.
   	▶ Check the harness or connector between the fuse (7.5A) in the engine compartment junction block and the ESP control module. Repair if necessary.

   
   

   

6. 6
   Disconnect the connector from the ESP control module.
7. 7
   Check the continuity between terminals 13 and 38 of the ESP control module harness-side connector and the ground point. Is there continuity?

   	▶ Check the wheel speed sensor circuit.
   	▶ Repair the open in the wire and the ground point.

   
   

   

8. 8
   Refer to DTC troubleshooting procedures.
9. 9
   Is this normal?

   	▶ Check the hydraulic circuit for leakage.
   	▶ Repair or replace the wheel speed sensor.

10. 10
    Check the hydraulic lines for leaks.
11. 11
    Is this normal?

    	▶ If the problem remains, replace the ESP control module.
    	▶ Repair the hydraulic line for leakage.

    

Check the power supply circuit. Check the ground circuit. Check the wheel speed sensor circuit. Check the hydraulic circuit for leaks. Detection condition

Symptom Condition	Possible Cause
Brake operation depends on driving conditions and road surface conditions, so diagnosis may be difficult. However, if a normal DTC is displayed, check the following possible causes. If the problem still occurs, replace the ESP control module.	Faulty power supply circuit Faulty wheel speed sensor circuit Faulty hydraulic circuit due to leakage Faulty HECU

Inspection Procedures. Check DTC.

1. 1
   Connect the GDS to the data link connector and turn the ignition switch ON.
2. 2
   Make sure that a DTC is output.
3. 3
   Is a DTC output?

   	▶ Check the wheel speed sensor circuit.
   	▶ Clear the DTC and recheck using GDS.

4. 4
   Refer to DTC troubleshooting procedures.
5. 5
   Is this normal?

   	▶ Check the stop lamp switch circuit.
   	▶ Repair or replace the wheel speed sensor.

6. 6
   Verify that the stop lamp illuminates when the brake pedal is depressed and goes off when the brake pedal is released.
7. 7
   Measure the voltage between terminal 23 of the ESP control module harness-side connector and body ground while the brake pedal is depressed.

   Specification: Approximately B+

   Is the voltage within specification?

   	▶ Check the hydraulic circuit for leakage.
   	▶ Repair the stop lamp switch. Repair the open circuit between the ESP control module and the stop lamp switch.

   
   

   

8. 8
   Refer to hydraulic lines.
9. 9
   Check the hydraulic lines for leaks.
10. 10
    Is this normal?

    	▶ If the problem remains, replace the ESP control module.
    	▶ Repair the hydraulic line for leakage.

    

Check the wheel speed sensor circuit. Check the stop lamp switch circuit. Check the hydraulic circuit for leaks. Detection condition

Symptom Condition	Possible Cause
A possible malfunction exists in the power supply (including ground) circuit for the diagnostic line.	Open in the wire Poor ground Faulty power supply circuit

Inspection Procedures. Check the power supply circuit for diagnosis.

1. 1
   Measure the voltage between terminal 16 of the data link connector and body ground.

   Specification: Approximately B+

   Is the voltage within specification?

   	▶ Check the ground circuit for diagnosis.
   	▶ Repair the open circuit in the wire. Check and replace the fuse from the engine compartment junction block.

   
   

   

2. 2
   Check the continuity between terminal 4 of the data link connector and body ground. Is there continuity?

   ▶ Repair the open circuit in the wire between terminal 4 of the data link connector and the ground point.

   
   

   

   

Check the ground circuit for diagnosis. Detection condition

Symptom Condition	Possible Cause
If communication with the GDS is not possible, the cause may be an open in the HECU power supply circuit or an open in the diagnostic output circuit.	Open in the wire Faulty HECU Faulty power supply circuit

Inspection Procedures. Check the CAN line integrity.

1. 1
   Disconnect the connector from the ESP control module.
2. 2
   Check the continuity between terminals 26, 14 of the ESP control module connector and terminals 3, 11 of the data link connector.
3. 3
   Is there continuity?

   	▶ Check the power supply to the ESP control module.
   	▶ Repair the open circuit in the wire.

4. 4
   Disconnect the connector from the ESP control module.
5. 5
   Turn the ignition on, and measure the voltage between terminal 29 of the ESP control module harness-side connector and body ground.

   Specification: Approximately B+

   Is the voltage within specification?

   	▶ Check for a poor ground connection.
   	▶ Check the harness or connector between the fuse (10A) in the engine compartment junction block and the ESP control module. Repair if necessary.

   
   

   

6. 6
   Check the continuity of the circuit between terminal 4 of the data link connector and the ground point.
7. 7
   Is there electrical current flow between the grounds?

   	▶ Replace the ESP control module and recheck.
   	▶ Repair the open in the wire or the poor ground connection.

   
   

   

   

Check the power supply to the ESP control module. Check for a poor ground connection. Detection condition

Symptom Condition	Possible Cause
When current flows in the HECU, the ABS warning lamp switches from ON to OFF as an initial check. Therefore, if the lamp does not illuminate, the cause may be an open in the lamp power circuit, a burned-out bulb, an open in both circuits between the ABS warning lamp and the HECU, or a faulty HECU.	Faulty ABS warning lamp bulb The blown fuse is related to the ABS in the engine compartment junction block. Faulty ABS warning lamp is damaged Faulty ABS warning lamp module Faulty HECU

Inspection Procedures. Check the problem.

1. 1
   Disconnect the connector from the ESP control module and turn the ignition on.
2. 2
   Does the ABS warning lamp illuminate?

   	▶ Recheck after replacing the ESP HECU.
   	▶ Check the power supply to the ABS warning lamp.

3. 3
   Disconnect the instrument cluster connector (M08) and turn the ignition ON.
4. 4
   Measure the voltage between terminal (M08) 39 of the instrument cluster harness side connector and body ground.

   Specification: Approximately B+

   

5. 5
   Is the voltage within specification?

   	▶ Check the CAN circuit and the resistance of the ABS warning lamp.
   	▶ Check whether the fuse is blown.

6. 6
   Disconnect the instrument cluster connector (M08) and turn the ignition OFF.
7. 7
   Measure the resistance between terminals (M08) 32 and 33 of the instrument cluster harness side connector.

   Specification: 60 Ω

   

8. 8
   Is the resistance within specification?

   	▶ Repair the ABS warning lamp or replace the instrument cluster assembly.
   	▶ Check the CAN electrical circuit of the ABS warning lamp.

9. 9
   Disconnect the instrument cluster (M08) connector and the ESP HECU connector, then turn the ignition off.
10. 10
    Check the continuity between terminal (M08) 32 of the instrument cluster harness-side connector and terminal 26 of the ESP HECU harness-side connector. Check the continuity between terminal (M08) 33 of the instrument cluster harness-side connector and terminal 14 of the ESP HECU harness-side connector.

    Specification: Less than 1 ohm

11. 11
    Is the resistance within specification?

    	▶ Repair the short circuit in the wiring between terminals 26, 14 of the ESP HECU harness connector and the ABS warning lamp module.
    	▶ Repair the open circuit in the wiring between terminals 26, 14 of the ESP HECU harness connector and the ABS warning lamp module.

    

Check the power supply to the ABS warning lamp. Check the resistance of the ABS warning lamp CAN circuit. Check the wiring of the ABS warning lamp CAN circuit. Detection condition

Symptom Condition	Possible Cause
If the HECU detects a malfunction, it illuminates the ABS warning lamp and simultaneously inhibits ABS control. At this time, the HECU stores the DTC in memory. Even though a normal code is output, if the ABS warning lamp remains on, the cause may be an open or short circuit in the ABS warning lamp circuit.	Open in the wire Faulty instrument cluster assembly Faulty ABS warning lamp module Faulty HECU

Inspection Procedures. Check the DTC output.

1. 1
   Connect the GDS to the 16-pin data link connector located behind the driver's side kick panel.
2. 2
   Check the DTC output using the GDS.
3. 3
   Is a DTC output?

   	▶ Perform the DTC troubleshooting procedure (refer to DTC troubleshooting).
   	▶ Check the CAN circuit and the resistance of the ABS warning lamp.

4. 4
   Disconnect the instrument cluster connector (M08) and turn the ignition OFF.
5. 5
   Measure the resistance between terminals (M08) 32 and 33 of the instrument cluster harness side connector.

   Specification: 60 Ω

   

6. 6
   Is the resistance within specification?

   	▶ Repair the ABS warning lamp or replace the instrument cluster assembly.
   	▶ Check the CAN circuit and the ABS warning lamp wiring.

7. 7
   Disconnect the instrument cluster (M08) connector and the ESP HECU connector, then turn the ignition off.
8. 8
   Check the continuity between terminal (M08) 32 of the instrument cluster harness-side connector and terminal 26 of the ESP HECU harness-side connector. Check the continuity between terminal (M08) 33 of the instrument cluster harness-side connector and terminal 14 of the ESP HECU harness-side connector.

   Specification: Less than 1 ohm

9. 9
   Is the resistance within specification?

   	▶ Repair the short circuit in the wiring between terminals 26, 14 of the ESP HECU harness connector and the ABS warning lamp module.
   	▶ Repair the open circuit in the wiring between terminals 26 and 14 of the ESP HECU wiring harness connector and the ABS warning lamp module.

Check the resistance of the ABS warning lamp CAN circuit. Check the CAN circuit wiring for the ABS warning lamp.