Last Modified: 05-13-2024 6.11:8.1.0 Doc ID: RM10000000277TR
Model Year Start: 2023 Model: Corolla Prod Date Range: [09/2022 -           ]
Title: HYBRID / BATTERY CONTROL: BATTERY ECU (for LITHIUM-ION BATTERY): REMOVAL; 2023 - 2025 MY Corolla Corolla HV [09/2022 -        ]

REMOVAL

CAUTION / NOTICE / HINT

The necessary procedures (adjustment, calibration, initialization or registration) that must be performed after parts are removed and installed, or replaced during battery ECU assembly removal/installation are shown below.

Necessary Procedures After Parts Removed/Installed/Replaced

Replaced Part or Performed Procedure

Necessary Procedure

Effect/Inoperative Function when Necessary Procedure not Performed

Link

Replacement of battery ECU assembly

Current sensor offset learning

DTCs are stored

2023 - 2025 MY Corolla Corolla HV [09/2022 -        ]; HYBRID / BATTERY CONTROL: HV RELAY ASSEMBLY (for LITHIUM-ION BATTERY): INSTALLATION+

CAUTION:

  • Orange wire harnesses and connectors indicate high-voltage circuits. To prevent electric shock, always follow the procedure described in the repair manual.

    Click here 2023 - 2025 MY Corolla HV [09/2022 -        ]; HYBRID / BATTERY CONTROL: HYBRID CONTROL SYSTEM (for LITHIUM-ION BATTERY with PA10): PRECAUTION

  • To prevent electric shock, wear insulated gloves when working on wire harnesses and components of the high voltage system.

NOTICE:

  • The type of battery ECU assembly to be used varies depending on the vehicle model.
  • If the wrong type of battery ECU assembly is installed, the power switch cannot be turned on (READY).
  • After installing the battery ECU assembly, perform the following to check that the power switch can be turned on (READY).
    • Turn the power switch on (READY).
    • Turn the power switch off and wait for 30 seconds or more.
    • Turn the power switch on (READY) again.
  • This procedure includes the removal of small-head bolts. Refer to Small-Head Bolts of Basic Repair Hint to identify the small-head bolts.

    Click here 2019 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [06/2018 -        ]; INTRODUCTION: REPAIR INSTRUCTION: PRECAUTION

  • After turning the power switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal.

    Click here 2023 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [09/2022 -        ]; SETUP: WHEN DISCONNECTING OR RECONNECTING BATTERY TERMINAL: BEFORE DISCONNECTING BATTERY

  • After turning the power switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work.

HINT:

When the cable is disconnected / reconnected to the auxiliary battery terminal, systems temporarily stop operating. However, each system has a function that completes learning the first time the system is used.

Learning completes when vehicle is driven

Effect/Inoperative Function when Necessary Procedure not Performed

Necessary Procedure

Link

Front Camera System (for TMC Made)

Drive the vehicle straight ahead at 15 km/h (9 mph) or more for 1 second or more.

2023 MY Corolla Corolla Hatchback Corolla HV GR Corolla [09/2022 - 11/2022]; ADVANCED DRIVER ASSISTANCE SYSTEM: FRONT CAMERA SYSTEM (for TMC Made): INITIALIZATION 2023 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [11/2022 -        ]; ADVANCED DRIVER ASSISTANCE SYSTEM: FRONT CAMERA SYSTEM: INITIALIZATION

PROCEDURE

1. PRECAUTION

Click here 2019 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [06/2018 -        ]; INTRODUCTION: REPAIR INSTRUCTION: PRECAUTION

2. WHEN REPLACING BATTERY ECU ASSEMBLY

HV battery learning values are stored in the battery ECU assembly and ECM and are used to detect malfunctions and illuminate the hybrid battery indicator light in the combination meter assembly. When either of these ECUs is replaced, the new ECU receives the HV battery learning values from the other ECU and stores them.

NOTICE:

  • Do not replace the battery ECU assembly and ECM at the same time as the HV battery learning values will be lost. However, if it is necessary to replace both ECUs at the same time, replace them by following the procedure below.
  • Do not replace the battery ECU assembly or ECM with a used one from another vehicle.

(a) Procedure when replacing both battery ECU assembly and ECM:

(1) Disconnect the cable from the negative (-) auxiliary battery terminal.

(2) Replace either ECU.

(3) Connect the cable to the negative (-) auxiliary battery terminal.

(4) Turn the power switch on (READY) and wait for 5 minutes or more.

(5) Turn the power switch off and disconnect the cable from the negative (-) auxiliary battery terminal.

(6) Replace the other ECU.

(7) Connect the cable to the negative (-) auxiliary battery terminal.

(8) Check that the power switch can be turned on (READY).

HINT:

If the battery ECU assembly and ECM are replaced at the same time without following the above procedure, replace either of the ECUs with its original one and then replace it again by following the above procedure. If the correct procedure is not followed, perform the procedure again from the beginning.

3. REMOVE SERVICE PLUG GRIP

Click here 2023 - 2025 MY Corolla Corolla HV [09/2022 -        ]; HYBRID / BATTERY CONTROL: SERVICE PLUG GRIP: REMOVAL

4. REMOVE CONNECTOR COVER ASSEMBLY

Click here 2023 - 2025 MY Corolla Corolla HV [09/2022 -        ]; HYBRID / BATTERY CONTROL: INVERTER WITH CONVERTER: REMOVAL+

5. CHECK TERMINAL VOLTAGE

Click here 2023 - 2025 MY Corolla Corolla HV [09/2022 -        ]; HYBRID / BATTERY CONTROL: INVERTER WITH CONVERTER: REMOVAL+

6. INSTALL CONNECTOR COVER ASSEMBLY

Click here 2023 - 2025 MY Corolla Corolla HV [09/2022 -        ]; HYBRID / BATTERY CONTROL: HV BATTERY (for LITHIUM-ION BATTERY): REMOVAL+

7. DISCONNECT REAR SEAT CENTER LAP TYPE BELT ASSEMBLY

Click here 2020 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [01/2019 -        ]; SEAT: REAR SEAT ASSEMBLY: REMOVAL+

8. REMOVE REAR SEAT CUSHION ASSEMBLY

Click here 2020 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [01/2019 -        ]; SEAT: REAR SEAT ASSEMBLY: REMOVAL+

9. REMOVE REAR SEAT CUSHION LOCK HOOK

Click here 2020 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [01/2019 -        ]; SEAT: REAR SEAT ASSEMBLY: REMOVAL+

10. REMOVE REAR DOOR SCUFF PLATE LH

Click here 2023 MY Corolla Corolla Hatchback Corolla HV GR Corolla [09/2022 - 11/2022]; INTERIOR PANELS / TRIM: ROOF HEADLINING (for Sedan): REMOVAL+ 2023 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [11/2022 -        ]; INTERIOR PANELS / TRIM: ROOF HEADLINING (for Sedan): REMOVAL+

11. REMOVE REAR UNDER SIDE COVER LH

Click here 2023 MY Corolla Corolla Hatchback Corolla HV GR Corolla [09/2022 - 11/2022]; INTERIOR PANELS / TRIM: ROOF HEADLINING (for Sedan): REMOVAL+ 2023 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [11/2022 -        ]; INTERIOR PANELS / TRIM: ROOF HEADLINING (for Sedan): REMOVAL+

12. REMOVE REAR DOOR SCUFF PLATE RH

HINT:

Use the same procedure as for the LH side.

13. REMOVE REAR UNDER SIDE COVER RH

HINT:

Use the same procedure as for the LH side.

14. REMOVE REAR UNDER COVER

Click here 2023 - 2025 MY Corolla Corolla HV [09/2022 -        ]; HYBRID / BATTERY CONTROL: BATTERY BLOWER: REMOVAL+

15. REMOVE REAR SEAT CUSHION LEG SUB-ASSEMBLY

Click here 2023 - 2025 MY Corolla Corolla HV [09/2022 -        ]; HYBRID / BATTERY CONTROL: BATTERY BLOWER: REMOVAL+

16. REMOVE NO. 1 HV BATTERY COVER PANEL RH

Click here 2023 - 2025 MY Corolla Corolla HV [09/2022 -        ]; HYBRID / BATTERY CONTROL: HV BATTERY (for LITHIUM-ION BATTERY): REMOVAL+

17. REMOVE UPPER NO. 1 HYBRID BATTERY COVER SUB-ASSEMBLY

CAUTION:

Be sure to wear insulated gloves and protective goggles.

(a) Remove the 8 bolts and upper No. 1 hybrid battery cover sub-assembly from the HV battery.

18. REMOVE BATTERY ECU ASSEMBLY

CAUTION:

Be sure to wear insulated gloves and protective goggles.

(a) Disconnect the 3 battery ECU assembly connectors.

NOTICE:

Insulate each disconnected high-voltage connector with insulating tape. Wrap the connector from the wire harness side to the end of the connector.

(b) Using an 8 mm socket wrench, remove the 2 bolts and battery ECU assembly from the HV battery.

NOTICE:

If the battery ECU assembly has been struck or dropped, replace it.