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INSPECTION PROCEDURE 5: Malfunction of Power Supply Circuit System
 
 
 
 
COMMENTS ON TROUBLE SYMPTOM
AWC-ECU power supply circuit, ground circuit, or AWC-ECU may have a problem.
 
 
PROBABLE CAUSES
  • Malfunction of ETACS-ECU
  • Damaged wiring harness and connectors
  • Malfunction of AWC-ECU

 
 
DIAGNOSTIC PROCEDURE
STEP 1. Check of the fuse No.13 and No.15.
Visually check for open circuit in the fuse No.13, No.15.
Is the check result normal?
Go to Step 6.
Go to Step 2.
 
STEP 2. Check the wiring harness between electronic control coupling solenoid (front) connector and AWC-ECU connector terminal FSL+.
Check the power supply line for short circuit.
Is the check result normal?
Go to Step 3.
Repair the wiring harness wire and/or connector(s), and then replace fuse No.13. Then go to Step 22.
 
STEP 3. Check the wiring harness between electronic control coupling solenoid (front) connector and AWC-ECU connector terminal FSL-.
Check the ground line for short to the power supply.
Is the check result normal?
Go to Step 4.
Repair the wiring harness wire and/or connector(s), and then replace fuse No.13. Then go to Step 22.
 
STEP 4. Check the wiring harness between electronic control coupling solenoid (center) connector and AWC-ECU connector terminal SOL+.
Check the power supply line for short circuit.
Is the check result normal?
Go to Step 5.
Repair the wiring harness wire and/or connector(s), and then replace fuse No.13. Then go to Step 22.
 
STEP 5. Check the wiring harness between electronic control coupling solenoid (center) connector and AWC-ECU connector terminal SOL-.
Check the ground line for short to the power supply.
Is the check result normal?
Go to Step 6.
Repair the wiring harness wire and/or connector(s), and then replace fuse No.13. Then go to Step 22.
 
STEP 6. Check of the electronic control coupling solenoid (front)
Refer to .
Is the check result normal?
Go to Step 7.
Repair the wiring harness wire and/or connector(s), and then replace fuse No.13. Then go to Step 22.
 
STEP 7. Check of the electronic control coupling solenoid (center)
Refer to GROUP 27C - On-vehicle Service .
Is the check result normal?
Go to Step 8.
Repair the wiring harness wire and/or connector(s), and then replace fuse No.13. Then go to Step 22.
 
STEP 8. Check the wiring harness between ETACS-ECU connector and AWC-ECU connector terminal BATT
Check the power supply for short circuit.
Is the check result normal?
Go to Step 9.
Repair the wiring harness wire and/or connector(s), and then replace fuse No.13. Then go to Step 22.
 
STEP 9. Check the wiring harness between ETACS-ECU connector and AWC-ECU connector terminal IG1
Check the power supply for short circuit.
Is the check result normal?
Replace the fuse Nos.13 and 15. Then go to Step 10.
Repair the wiring harness wire and/or connector(s), and then replace fuse No.15. Then go to Step 22.
 
STEP 10. Voltage measurement at ETACS-ECU connector
Disconnect the connector, and measure the voltage between terminal +B1 and body ground at the wiring harness side.
OK: Battery positive voltage
Is the check result normal?
Go to Step 12.
Go to Step 11.
 
STEP 11. Check the wiring harness between ETACS-ECU connector terminal +B1 and fusible link No.2
Check the power supply line for open circuit or short circuit.
Is the check result normal?
Go to Step 22.
Repair the defective connector or the wiring harness. Then go to Step 22.
 
STEP 12. Voltage measurement at the ETACS-ECU connector
(1) Disconnect the connector, and measure the voltage between terminal IG1 and body ground at the wiring harness side.
(2) Turn the ignition switch to the ON position.
OK: Battery positive voltage
Is the check result normal?
Go to Step 14.
Go to Step 13.
 
STEP 13. Check the wiring harness between ETACS-ECU connector terminal IG1 and J/C(2).
Check the power supply line for open circuit or short circuit.
Is the check result normal?
Go to Step 22.
Repair the defective connector or the wiring harness. Then go to Step 22.
 
STEP 14. Voltage measurement at the AWC-ECU connector
Disconnect the connector, and measure the voltage between terminal BATT and body ground at the wiring harness side.
OK: Battery positive voltage
Is the check result normal?
Go to Step 16.
Go to Step 15.
 
STEP 15. Check the wiring harness between ETACS-ECU connector and AWC-ECU connector terminal BATT.
Check the power supply line for open circuit.
Is the check result normal?
Go to Step 22.
Repair the defective connector or the wiring harness. Then go to Step 22.
 
STEP 16. Voltage measurement at the AWC-ECU connector
(1) Disconnect the connector, and measure the voltage between terminal IG1 and body ground at the wiring harness side.
(2) Turn the ignition switch to the ON position.
OK: Battery positive voltage
Is the check result normal?
Go to Step 18.
Go to Step 17.
 
STEP 17. Check the wiring harness between ETACS-ECU connector terminal IG1 and AWC-ECU connector terminal IG1.
Check the power supply line for open circuit.
Is the check result normal?
Go to Step 22.
Repair the defective connector or the wiring harness. Then go to Step 22.
 
STEP 18. Measure the resistance at the AWC-ECU connector.
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Resistance between AWC-ECU connector terminal GND1 and body ground.
OK: Continuity exists (2 Ω or less)
Is the check result normal?
Go to Step 20.
Go to Step 19.
 
STEP 19. Check the wiring harness between AWC-ECU connector terminal GND1 and body ground.
Check the ground line for open circuit.
Is the check result normal?
Go to Step 22.
Repair the defective connector or the wiring harness. Then go to Step 22.
 
STEP 20. Retest the system.
Does the malfunction occur again?
Replace the ETACS-ECU (Refer to GROUP 54A - ETACS-ECU ).Then go to Step 21.
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/How to Cope with Intermittent Malfunctions ).
 
STEP 21. Retest the system.
Does the malfunction occur again?
Replace the AWC-ECU (Refer to ). Then go to Step 22.
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/How to Cope with Intermittent Malfunctions ).
 
STEP 22. Retest the system.
Does the malfunction occur again?
Return to Step 1.
This diagnosis is complete.