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Inspection Procedure 4: ABS warning light does not illuminate when ignition switch is turned to the ON position (engine stopped).
 
 
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 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
  • 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. Using scan tool (M.U.T.-IIISE), diagnose the CAN bus line.
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn the ignition switch to the "LOCK" (OFF) position 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 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 .)
 
STEP 2. Using scan tool (M.U.T.-IIISE), check other 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. Using scan tool (M.U.T.-IIISE), check 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 6: Indicator (AUTO)
Is the check result normal?
Go to Step 4.
Replace the combination meter.
 
STEP 4. ETACS-ECU coding data check.
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?
This diagnosis is complete.
Replace the ETACS-ECU (Refer to GROUP 54A - ETACS-ECU ).
 
STEP 6. Using scan tool (M.U.T.-IIISE), check other system DTC.
Using scan tool (M.U.T.-IIISE), check that DTC 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. Using scan tool (M.U.T.-IIISE), check other system DTC.
Using scan tool (M.U.T.-IIISE), check that DTC 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 ).