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Inspection Procedure 18: ESS inoperative or improper operative
 
 
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.
 
 
COMMENTS ON TROUBLE SYMPTOM
In the case of this trouble symptom, ESS operation may be disabled. A DTC may be set by the ASC system.
noteBefore carrying out the troubleshooting, ask the user and confirm the driving conditions when the failure has occurred.
 
 
 
TROUBLESHOOTING HINTS
  • Low battery voltage
  • Wiring harness or connector failure of CAN bus line
  • The ASC-ECU is defective.
  • Different ETACS-ECU, abnormal variant coding information
  • Different ASC-ECU.
  • Malfunction of ETACS-ECU.
 
 
 
 
DIAGNOSIS
STEP 1. Hydraulic unit (integrated with ASC-ECU) check
Check the hydraulic unit (integrated with ASC-ECU) part No.
Is the check result normal?
Go to Step 2.
Replace the hydraulic unit (integrated with ASC-ECU) (Refer to ). Then go to Step 2.
 
STEP 2. ETACS-ECU check
Check the ETACS-ECU part No.
Is the check result normal?
Go to Step 3.
Replace ETACS-ECU (Refer to GROUP 54A - ETACS-ECU ). Then go to Step 3.
 
STEP 3. DTC check
Use scan tool (M.U.T.-III) to check the DTC for the ASC system and ETACS-ECU (Refer to and GROUP 54A - ETACS/DTC chart ).
Is the check result normal?
Go to Step 4.
Carry out the diagnosis for the DTC. (Refer to or GROUP 54A - ETACS/DTC chart ). Then go to Step 4.
 
STEP 4. Scan tool (M.U.T.-III) actuator test
(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) Perform the following actuator test, and check if the ESS operation (Refer to ).
  • Item No. 10: ESS test mode
Is the check result normal?
This diagnosis is complete.
Go to Step 5.
 
STEP 5. Check ETACS coding data
Refer to GROUP 00 - Precautions before Service/Coding List .
Is the check result normal?
Go to Step 6.
Replace ETACS-ECU (Refer to GROUP 54A - ETACS-ECU ). Then go to Step 9.
 
STEP 6. Check the ASC-ECU power supply circuit.
Refer to .
Is the check result normal?
Go to Step 7.
Carry out the diagnosis of ASC-ECU power supply circuit system (Refer to ). Then go to Step 9.
 
STEP 7. Scan tool (M.U.T.-III) actuator test
Perform the following actuator test, and check if the ESS operation (Refer to ).
  • Item No. 10: ESS test mode
Is the check result normal?
This diagnosis is complete.
Replace ETACS-ECU (Refer to GROUP 54A - ETACS-ECU ). Then go to Step 8.
 
STEP 8. Scan tool (M.U.T.-III) actuator test
Perform the following actuator test, and check if the ESS operation (Refer to ).
  • Item No. 10: ESS test mode
Is the check result normal?
This diagnosis is complete.
Replace the hydraulic unit (integrated with ASC-ECU) (Refer to ). Then go to Step 9.
 
STEP 9. Scan tool (M.U.T.-III) actuator test
Perform the following actuator test, and check if the ESS operation (Refer to ).
  • Item No. 10: ESS test mode
Is the check result normal?
This diagnosis is complete.
Return to Step 1.