Inspection Procedure 1: Communication with Engine-ECU is Not Possible




OPERATION




COMMENTS ON TROUBLE SYMPTOM




PROBABLE CAUSES




DIAGNOSIS PROCEDURE


STEP 1. Check the Vehicle Communication Interface (V.C.I.) operations



  • Connect the M.U.T.-III to the diagnosis connector.
  • When the power of Vehicle Communication Interface (V.C.I.) is turned to ON, the indicator lamp of the Vehicle Communication Interface (V.C.I.) illuminates in green.
OK: The indicator lamp of the Vehicle Communication Interface (V.C.I.) illuminates in green.

Q. Is the check result normal?

Go to Step 10.
Go to Step 2.

STEP 2. Check auxiliary battery.



  • Check auxiliary battery (Refer to GROUP 54A <PHEV> - Auxiliary Battery - On-vehicle Service - Auxiliary Battery Test ).

Q. Is the check result normal?

Go to Step 3.
Replace the auxiliary battery.

STEP 3. Perform voltage measurement at diagnosis connector.



  • Voltage between terminal power supply line and body earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 6.
Go to Step 4.

STEP 4. Check harness between ETACS-ECU connector terminal MUT and diagnosis connector terminal.



  • Check power supply line for open/short circuit.

Q. Is the check result normal?

Go to Step 5.
Repair or replace the connector, or repair the damaged harness wire.

STEP 5. Check harness between auxiliary battery and ETACS-ECU connector terminal +B1.



  • Check power supply line for open/short circuit.

Q. Is the check result normal?

Check fuse in the ETACS-ECU, and replace if necessary. If the fuse is normal, replace the ETACS-ECU.
Repair or replace the connector, or repair the damaged harness wire.

STEP 6. Perform resistance measurement at diagnosis connector.



  • Resistance between terminals earth lines and body earth.
OK: Continuity (2 Ω or less)

Q. Is the check result normal?

Go to Step 7.

    Repair or replace the connector, or check and repair the harness between the diagnosis connector terminal earth lines and body earth.

    • Check earthing line for open circuit and damage.

STEP 7. Continuity check on ETACS-ECU connectors



  • Disconnect connectors, and measure at ETACS-ECU side.
  • Continuity check between terminal +B1 and MUT.
OK: Continuity

Q. Is the check result normal?

Go to Step 8.
Repair or replace the connector, or check fuse in the ETACS-ECU, and replace if necessary. If the fuse is normal, replace the ETACS-ECU.

STEP 8. Check harness between auxiliary battery and ETACS-ECU connector terminal +B1.



  • Check power supply line for damage.

Q. Is the check result normal?

Go to Step 9.
Repair or replace the connector, or repair the damaged harness wire.

STEP 9. Check harness between ETACS-ECU connector terminal MUT and diagnosis connector terminal.



  • Check power supply line for damage.

Q. Is the check result normal?

Refer to the M.U.T.-III reference manual.
Repair or replace the connector, or repair the damaged harness wire.

STEP 10. M.U.T.-III CAN bus diagnosis



  • Use M.U.T.-III, perform CAN bus line diagnosis.

Q. Is the check result normal?

Check Inspection Procedure - engine-ECU power supply, engine control relay, ignition switch-IG1 system (Refer to ).
Perform troubleshooting for CAN (Refer to GROUP 54C <PHEV> - Troubleshooting - CAN Bus Diagnostics Table ).