INSPECTION PROCEDURE 3: AWC-ECU power supply circuit malfunction (Control mode is not displayed.)


POWER SUPPLY SYSTEM CIRCUIT



caution
  • If there is any problem in the CAN bus lines, an incorrect trouble symptom may occur. Prior to this diagnosis, always diagnose the CAN bus lines.
  • Whenever the ECU is replaced, ensure that the CAN bus lines are normal.

COMMENTS ON TROUBLE SYMPTOM



PROBABLE CAUSES



  • Malfunction of the ETACS-ECU
  • Damaged harness wires and connectors
  • Malfunction of AWC-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics.
Use M.U.T.-III to perform the CAN bus diagnosis.

Q. Is the check result normal?
Go to Step 3.
Repair the CAN bus lines. (Refer to GROUP 54C - Troubleshooting ). After repairing the CAN bus line, go to Step 2.

STEP 2. Retest the system.

Q. Is the check result normal?
Intermittent malfunction. (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
Go to Step 3.

STEP 3. Voltage measurement at C-44 AWC-ECU connector
Disconnect the connector, and measure the voltage between terminal No.12 and earth at the wiring harness side.
OK: System voltage

Q. Is the check result normal?
Go to Step 6.
Go to Step 4.

STEP 4. AWC-ECU connector, ETACS-ECU connector check: C-44, C-315

Q. Is the check result normal?
Go to Step 5.
Repair the defective connector. Then go to Step 13.

STEP 5. Check the wiring harness between C-44 AWC-ECU connector terminal No.12 and C-315 ETACS-ECU connector terminal No.4.
Check the wiring harness for open circuit.

Q. Is the check result normal?
Go to Step 12.
Check C-27 intermediate connector, C-39 J/C (1) <RHD>. When no problem is found, repair the wiring harness. Then go to Step 13.

STEP 6. Voltage measurement at C-44 AWC-ECU connector
(1)Disconnect the connector, and measure the voltage between terminal No.16 and earth at the wiring harness side.
(2)Turn the ignition switch to the "ON" position.
OK: System voltage

Q. Is the check result normal?
Go to Step 9.
Go to Step 7.

STEP 7. AWC-ECU connector, ETACS-ECU connector check: C-44, C-313

Q. Is the check result normal?
Go to Step 8.
Repair the defective connector. Then go to Step 13.

STEP 8. Check the wiring harness between C-44 AWC-ECU connector terminal No.16 and C-313 ETACS-ECU connector terminal No.2.
Check the wiring harness for open circuit.

Q. Is the check result normal?
Go to Step 12.
Check C-30 J/C (4) <RHD>. When no problem is found, repair the wiring harness. Then go to Step 11.

STEP 9. AWC-ECU connector check: C-44

Q. Is the check result normal?
Go to Step 10.
Repair the defective connector. Then go to Step 13.

TEP 10. Check the wiring harness between C-44 AWC-ECU connector terminal No.13 and body earth.
Check the wiring harness for open circuit.

Q. Is the check result normal?
Go to Step 11.
Repair the wiring harness. Then go to Step 13.

STEP 11. M.U.T.-III data list.
Item No.43: Battery voltage (Refer to data list reference table ).

Q. Is the check result normal?
Intermittent malfunction. (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
Replace the AWC-ECU. (Refer to ). Then go to Step 13.

STEP 12. Retest the system.

Q. Is the check result normal?
Intermittent malfunction. (Refer to GROUP 00 - How to Cope with Intermittent Malfunction .)
Replace the ETACS-ECU. (Refer to GROUP 54A - ETACS-ECU ). Then go to Step 13.

STEP 13. Retest the system.

Q. Is the check result normal?
Return to Step 1.
This diagnosis is complete.