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Inspection Procedure 4: ABS warning light does not illuminate when electric motor switch is turned 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 ).
  • Before replacing the ECU, ensure that the communication circuit is normal.
 
 
OPERATION
  • ASC-ECU sends the illumination request signal of the ABS warning light to the combination meter through ETACS-ECU via CAN communication.
  • ASC-ECU illuminates the ABS warning light via ETACS-ECU for approximately 3 seconds for valve check with the electric motor 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.
 
 
 
TROUBLESHOOTING HINTS
  • Damaged wiring harness and connectors
  • Malfunction of ETACS-ECU
  • Combination meter malfunction
  • ASC-ECU malfunction
  • Malfunction of coding data for ETACS-ECU
 
 
 
 
DIAGNOSIS
STEP 1. Scan tool (M.U.T.-IIISE) CAN bus diagnostics.
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn off the power supply mode of the electric motor switch before connecting or disconnecting scan tool (M.U.T.-IIISE).
Connect scan tool (M.U.T.-IIISE). Refer to "How to connect the Scan Tool (M.U.T.-IIISE) ."
(2) Turn on the power supply mode of the electric motor switch.
(3) Diagnose the CAN bus line.
(4) Turn off the power supply mode of the electric motor switch.
Is the check result normal?
Go to Step 2.
Repair the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table .)
 
STEP 2. Scan tool (M.U.T.-IIISE) DTC.
Use scan tool (M.U.T.-IIISE) to check the DTC for the ASC system (Refer to ).
Is the DTC set?
Carry out the diagnosis for the DTC (Refer to ).
Go to Step 3.
 
STEP 3. Scan tool (M.U.T.-IIISE) 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. 6: Indicator (AUTO)
Is the check result normal?
Go to Step 4.
Replace the combination meter.
 
STEP 4. ETACS-ECU coding data check.
Use scan tool (M.U.T.-IIISE) to check if coding data stored in ETACS-ECU is normal (Refer to GROUP 00 - Precautions before Service/Coding List ).
Is the check result normal?
Go to Step 6.
Go to Step 5.
 
STEP 5. ETACS-ECU coding data check.
Perform the variant coding to the ETACS-ECU.
Is the check result normal?
Go to Step 8.
Replace the ETACS-ECU (Refer to GROUP 54A - ETACS-ECU ).
 
STEP 6. Scan tool (M.U.T.-IIISE) DTC for other systems.
Using scan tool (M.U.T.-IIISE), 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/Troubleshooting ).
Go to Step 7.
 
STEP 7. Scan tool (M.U.T.-IIISE) DTC for other systems.
Using scan tool (M.U.T.-IIISE), check that DTC No.U0121 is not set in the ETACS system.
Is the DTC set?
Troubleshoot the ETACS-ECU (Refer to GROUP 54A - ETACS-ECU/Troubleshooting ).
Go to Step 8.
 
STEP 8. Retest the system.
Does the ABS warning light turn ON and OFF normally?
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/How to Cope with Intermittent Malfunction ).
Replace the hydraulic unit (integrated with ASC-ECU) (Refer to ).