Inspection Procedure 1: M.U.T.-III cannot Communicate with the Electronic Control 4WD System.

COMMENTS ON TROUBLE SYMPTOM



PROBABLE CAUSES



  • Damaged wiring harness and connectors
  • 4WD-ECU malfunction

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics
Use M.U.T.-III to diagnose the CAN bus lines.

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

STEP 2. Check the following connector:
Check the C-130 4WD-ECU connector for improper engagement, terminal damage or terminal drawn in the connector case.

Q. Are the connectors and terminals in good condition?
Go to Step 3.
Repair the connector(s) or terminal(s). Then go to Step 8.

STEP 3. Voltage measurement at the 4WD-ECU connector
(1)Disconnect the C-130 4WD-ECU connector.
(2)Turn the ignition switch to the ON position.
(3)Measure the voltage between the C-130 wiring harness side connector terminals No. 4 and the body earth.
OK: Battery voltage

Q. Is the check result normal?
Go to Step 5.
Go to Step 4.

STEP 4. Wiring harness check
note Before the wiring harness inspection, inspect the C-313 and C-309 ETACS-ECU connectors, and repair if necessary.
Check the wiring harness between the C-130 4WD-ECU connector (terminal No. 4) and the C-309 ETACS-ECU connector (terminal No. 1) for damage or other problem.

Q. Is the wiring harness in good condition?
Go to Step 7.
Repair the wiring harness. Then go to Step 8.

STEP 5. Resistance measurement at the 4WD-ECU connector
(1)Disconnect the C-130 4WD-ECU connector.
(2)Measure the resistance between the C-130 wiring harness side connector terminals No. 10 and the body earth.
OK: 2 Ω or less

Q. Is the check result normal?
Go to Step 7.
Go to Step 6.

STEP 6. Wiring harness check
Check the wiring harness between the C-130 4WD-ECU connector (terminal No. 10) and the body earth (No. 9 or No. 18) for damage or other problem.

Q. Is the wiring harness in good condition?
Go to Step 7.
Repair the wiring harness. Then go to Step 8.

STEP 7. Retest the system.

Q. Does the malfunction occur again?
Replace 4WD-ECU. (Refer to .) Then go to Step 8.
The trouble can be an intermittent malfunction. (Refer to GROUP 00 - How to Cope with Intermittent Malfunction .)

STEP 8. Check whether the diagnosis code is reset.

Q. Does the malfunction occur again?
Diagnose again from Step 1.
This diagnosis is complete.