Inspection Procedure 4: When the ignition switch is turned to the "ON" position (engine stopped), the ABS warning lamp does not illuminate.


caution
  • If there is any problem in the CAN bus lines, an incorrect diagnosis code may be set. Prior to this diagnosis, diagnose the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table ).
  • Whenever ECU is replaced, ensure that the CAN bus lines are normal.
  • When the hydraulic unit (integrated with ASTC-ECU) is replaced, always carry out the calibration of the steering wheel sensor and the G and yaw rate sensor (Refer to ).

OPERATION



COMMENTS ON TROUBLE SYMPTOM


This may be caused by faults in the CAN bus line, ETACS-ECU, combination meter or ASTC-ECU.

PROBABLE CAUSES



DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnosis
Use the M.U.T.-III to diagnose the CAN bus lines.

Q. Is the check result normal?
Go to Step 2.
Repair the CAN bus line. (Refer to GROUP 54C - Troubleshooting .) Then go to Step 7.

STEP 2. M.U.T.-III diagnosis code
Use M.U.T.-III to check the diagnosis code for the ASTC system.

Q. Is the diagnosis code set?
Carry out the diagnosis for the diagnosis code (Refer to ).
Go to Step 3.

STEP 3. Coding data check
Using M.U.T.-III, check if any abnormality is present to the coding data which are stored in the ETACS-ECU.

Q. Is the check result normal?
Go to Step 4.
Replace the ETACS-ECU. (Refer to GROUP 54A - ETACS-ECU .) Then go to Step 7.

STEP 4. M.U.T.-III Diagnosis code of other systems
Use M.U.T.-III to check if the diagnosis code is set in the combination meter system.

Q. Is the diagnosis code set?
Perform troubleshooting for the combination meter. (Refer to GROUP 54A - Combination Meter, Troubleshooting .) Then go to Step 7.
Go to Step 5.

STEP 5. M.U.T.-III Diagnosis code of other systems
Using M.U.T.-III, check that the diagnosis code is set in the ETACS system.

Q. Is the diagnosis code set?
Perform troubleshooting for ETACS-ECU. (Refer to GROUP 54A - ETACS, Troubleshooting .) Then go to Step 7.
Go to Step 6.

STEP 6. Retest the system

Q. Does the ABS warning lamp turn ON and OFF normally?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
Replace the hydraulic unit assembly (integrated with ASTC-ECU) (Refer to ). Then go to Step 7.

STEP 7. Retest the system

Q. Does the ABS warning lamp turn ON and OFF normally?
This diagnosis is complete.
Return to Step 1.