Inspection Procedure 5: Brake warning light does not illuminate when the ignition switch is turned to ON.
caution
If there is any problem in the CAN bus lines, an incorrect DTC 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.
OPERATION
ASC-ECU sends the illumination request signal of the break warning light to the combination meter through ETACS-ECU via the CAN communication.
ASC-ECU illuminates brake warning light via ETACS-ECU for approximately 3 seconds for bulb check with the ignition switch turned to the ON position.
COMMENTS ON TROUBLE SYMPTOM
This may be caused by faults in the CAN bus line, ETACS-ECU, combination meter or ASC-ECU.
PROBABLE CAUSES
Combination meter malfunction
ASC-ECU malfunction
DIAGNOSIS
STEP 1. Using scan tool (M.U.T.-IIISE) special function
Perform the following special function by the combination meter system, and check if the ABS warning light illuminates (Refer to GROUP 54A - Combination Meter/Special function table ).
Item No.9: Indicator (AUTO)
Is the check result normal?
Go to Step 2.
Replace the combination meter (Refer to GROUP 54A - Combination Meter ).
STEP 2. Retest the system.
Does the brake warning light turn ON and OFF
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/How to Cope with Intermittent Malfunctions ).