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Inspection Procedure 7: ASC warning light stays ON after the engine is started.
 
 
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 ASC warning light to the combination meter through ETACS-ECU via the CAN communication.
 
 
 
COMMENTS ON TROUBLE SYMPTOM
This may be caused by faults in the CAN bus line, ETACS-ECU, combination meter or ASC-ECU.
 
 
 
TROUBLESHOOTING HINTS
  • Damaged wiring harness and connectors
  • Malfunction of ETACS-ECU
  • Combination meter malfunction
  • ASC-ECU malfunction
  • Control is disabled due to the low voltage
    noteDue to the abnormality in the supply voltage, the DTC may not be set even when the ASC light illuminates.
 
 
 
 
DIAGNOSIS
STEP 1. Scan tool (M.U.T.-III) CAN bus diagnosis
(1)
cautionTo prevent damage to scan tool (M.U.T.-III), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-III).
Connect scan tool (M.U.T.-III). Refer to "How to connect the Scan Tool (M.U.T.-III) ."
(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the check result normal?
Go to Step 2.
Repair the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table ). Then go to Step 8.
 
STEP 2. Scan tool (M.U.T.-III) DTC
Use scan tool (M.U.T.-III) to check the DTC for the ASC system.
Is the DTC set?
Carry out the diagnosis for the DTC (Refer to ).
Go to Step 3.
 
STEP 3. Scan tool (M.U.T.-III) Special Function for other system
Perform the following special function by the combination meter system, and check if the ASC warning light illuminates (Refer to GROUP 54A - Combination Meter ).
  • Item No. 2: LCD (AUTO)
  • Item No. 6: Indicator (AUTO)
Is the check result normal?
Go to Step 4.
Replace the combination meter. Then go to Step 8.
 
STEP 4. Check the ASC-ECU power supply circuit system.
Refer to .
Is the check result normal?
Go to Step 5.
Diagnose the power supply circuit of the ASC-ECU (Refer to ).
 
STEP 5. Scan tool (M.U.T.-III) other system DTC
Using scan tool (M.U.T.-III), check that DTC No.U0141 is not set in the combination meter system.
Is the DTC set?
Diagnose the combination meter (Refer to GROUP 54A - Combination Meter/DTC ). Then go to Step 8.
Go to Step 6.
 
STEP 6. Scan tool (M.U.T.-III) other system DTC
Using scan tool (M.U.T.-III), check that DTC No.U0121 is not set in the ETACS system.
Is the DTC set?
Perform troubleshooting on ETACS-ECU (Refer to GROUP 54A - ETACS/DTC ). Then go to Step 8.
Go to Step 7.
 
STEP 7. Retest the system.
Does the ASC warning light turn ON and OFF normally?
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/How to Cope with Intermittent Malfunctions ).
Replace the hydraulic unit (integrated with ASC-ECU) (Refer to ), and then go to Step 8.
 
STEP 8. Retest the system.
Does the ASC light turn ON and OFF normally?
This diagnosis is complete.
Return to Step 1.