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Inspection Procedure 8: ASC OFF 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 ASC OFF light to the combination meter through ETACS-ECU via CAN communication.
  • By the operation of ASC OFF switch, the ASC OFF light illuminates when the ASC function is stopped.
  • When the ASC OFF switch is pressed for 3 seconds or more, the ASC system turns OFF.
  • When the ASC OFF switch is pressed for 15 seconds or more, the ASC is kept in ON state and the system cannot be turned OFF until the ignition switch is turned to the ON position next time.
 
 
 
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
 
 
 
 
DIAGNOSIS
STEP 1. Scan tool (M.U.T.-III) CAN bus diagnostics
(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 ABS warning light illuminates (Refer to GROUP 54A - Combination Meter ).
  • Item No. 2: LCD (AUTO)
Is the check result normal?
Go to Step 4.
Replace the combination meter. Then go to Step 8.
 
STEP 4. Scan tool (M.U.T.-III) data list for other system
Check the ETACS-ECU system data list.
  • ASC OFF switch: During ON operation
 
Item No. Item nameNormal condition
281ASC/TCL OFF switchON
Item No. Item nameNormal condition
281ASC/TCL OFF switchON
Is the check result normal?
Go to Step 5.
Refer to GROUP 54A - ETACS, Inspection Procedure 15 "The ASC OFF switch signal is not received." .
 
STEP 5. Scan tool (M.U.T.-III) DTC for other systems
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 ). Then go to Step 8.
Go to Step 6.
 
STEP 6. Scan tool (M.U.T.-III) DTC for other systems
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 ). Then go to Step 7.
Go to Step 7.
 
STEP 7. Retest the system.
Does ASC OFF 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 ). Then go to Step 8.
 
STEP 8. Retest the system.
Does ASC OFF light turn ON and OFF normally?
This diagnosis is complete.
Return to Step 1.