Code No. P1A4D: EV-ECU control power supply voltage abnormal












TROUBLE JUDGEMENT


Check Condition
  • The electric motor switch is "ON" position or while the traction battery is charged.
Judgement Criterion
  • The EV-ECU control power supply voltage is less than 8 V.
or

  • The EV-ECU control power supply voltage is more than 16 V.

FAIL-SAFE AND BACKUP FUNCTION



  • Not available

PROBABLE CAUSES



  • The auxiliary battery is failed.
  • When starting at the voltage more than 16 V from the outside of the vehicle
  • The installation of the auxiliary battery terminal is failed.
  • Open circuits of EV control relay circuit, short circuits to earth or damage; poor contact of connector.
  • The BMU is failed.

DIAGNOSIS PROCEDURE


STEP 1. Auxiliary battery condition check


Q. Does the auxiliary battery start at the voltage more than 16 V from the outside of the vehicle recently?

Erase the diagnosis code, check end.
Go to Step 2.

STEP 2. Auxiliary battery condition check


Q. Is the installation status of the auxiliary battery terminal is abnormal?

Repair.
Go to Step 3.

STEP 3. M.U.T.-III other system diagnosis code.


Q. Is the diagnosis code of EV-ECU system set?

Check EV-ECU system (Refer to ).
Go to Step 4.

STEP 4. Check auxiliary battery



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

Q. Is the check result normal?

Go to Step 5.
Replace the auxiliary battery.

STEP 5. Connector check: C-107 BMU connector


Q. Is the check result normal?

Go to Step 6.
Repair.

STEP 6. Perform voltage measurement at C-107 BMU connector.



  • Disconnect connector, and measure at harness side.
  • Electric motor switch: ON
  • Voltage between terminal No. 2 and earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 8.
Go to Step 7.

STEP 7. Connector check: A-08X EV control relay connector


Q. Is the check result normal?


    Check intermediate connector B-27, and repair if necessary. If intermediate connector is normal, check and repair harness between A-08X (terminal No. 1) EV control relay connector and C-107 (terminal No. 2) BMU connector.

    • Check power supply line for open circuit, short circuit to earth
Repair.

STEP 8. Check harness between A-08X (terminal No. 1) EV control relay connector and C-107 (terminal No. 2) BMU connector.


note Before checking harness, check intermediate connector B-27, and repair if necessary.

  • Check power supply line for damage.

Q. Is the check result normal?

Go to Step 9.
Repair.

STEP 9. M.U.T.-III diagnosis code.


Q. Is the diagnosis code set?

Replace the BMU.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).




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