Toyota Prius: Battery Ecu (for Hev Model)

Toyota Prius (XW60) 2023-2025 Service Manual / Engine/Hybrid System / Hybrid / Battery Control / Battery Ecu (for Hev Model)

Removal
Installation

Removal

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 Procedures	Effect/Inoperative Function when Necessary Procedure not Performed	Link
Replacement of battery ECU assembly	Current sensor offset learning	DTCs are stored

CAUTION:

Orange wire harnesses and connectors indicate high-voltage circuits. To prevent electric shock, always follow the procedure described in the repair manual.
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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 Toyota Prius vehicle model.
If the wrong type of battery ECU assembly is installed, the ignition switch cannot be turned on (READY).
After installing the battery ECU assembly, perform the following to check that the ignition switch can be turned on (READY).
- Turn the ignition switch to ON (READY).
- Turn the ignition switch off and wait for 30 seconds or more.
- Turn the ignition 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.
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After turning the power switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal.
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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.

Items for which learning is completed by driving the Toyota Prius vehicle

Effect/Inoperative Function When Necessary Procedures are not Performed	Necessary Procedures	Link
Front Camera System	Drive the Toyota Prius vehicle straight ahead at 35 km/h (22 mph) or more for 5 seconds or more.

Items for which learning is completed by operating the vehicle normally

Effect/Inoperative Function When Necessary Procedures are not Performed	Necessary Procedures	Link
1: w/o Power Back Door System 2: w/ Power Back Door System
Power Door Lock Control System*1 Back door opener	Perform door unlock operation with door control switch or electrical key transmitter sub-assembly switch.
Power Back Door System*2	Reset back door close position
Air Conditioning System	After the ignition switch is turned to ON, the servo motor standard position is recognized.	-

CAUTION / NOTICE / HINT

COMPONENTS (REMOVAL)

Procedure		Part Name Code
1	PRECAUTION	-		-	-
2	WHEN REPLACING BATTERY ECU ASSEMBLY	-		-	-
3	SERVICE PLUG GRIP	G3834	-	-	-

Procedure		Part Name Code
4	FRONT WIPER ARM HEAD CAP	85292B		-	-
5	SHIELD CAP	85247		-	-
6	FRONT WIPER ARM AND BLADE ASSEMBLY LH	-	-	-	-
7	FRONT WIPER ARM AND BLADE ASSEMBLY RH	-	-	-	-
8	WINDSHIELD LOWER OUTSIDE MOULDING LH	75536D		-	-
9	WINDSHIELD LOWER OUTSIDE MOULDING RH	75535F	-	-	-
10	COWL WATER EXTRACT SHIELD LH	55754F	-	-	-
11	COWL WATER EXTRACT SHIELD RH	55753D	-	-	-
12	COWL TOP VENTILATOR LOUVER SUB-ASSEMBLY	55708	-	-	-
13	CHECK TERMINAL VOLTAGE	-		-	-
14	COWL TOP VENTILATOR LOUVER SUB-ASSEMBLY	55708		-	-
15	COWL WATER EXTRACT SHIELD RH	55753D	-	-	-
16	COWL WATER EXTRACT SHIELD LH	55754F	-	-	-
17	WINDSHIELD LOWER OUTSIDE MOULDING LH	75536D	-	-	-
18	WINDSHIELD LOWER OUTSIDE MOULDING RH	75535F	-	-	-
19	FRONT WIPER ARM AND BLADE ASSEMBLY LH	-		-	-
20	FRONT WIPER ARM AND BLADE ASSEMBLY RH	-		-	-
21	SHIELD CAP	85247	-	-	-
22	FRONT WIPER ARM HEAD CAP	85292B	-	-	-

*A	for M20A-FXS	*B	for 2ZR-FXE
*1	Connector Cover Assembly	-	-
	Tightening torque for "Major areas involving basic Toyota Prius vehicle performance such as moving/turning/stopping" : Nm (kgfcm, ft.*lbf)		Nm (kgfcm, ft.*lbf): Specified torque

Procedure		Part Name Code
23	REAR CENTER SEAT OUTER BELT ASSEMBLY	73350C		-	-
24	REAR SEAT CUSHION ASSEMBLY	-		-	-
25	REAR SEAT CUSHION LOCK HOOK	72693	-	-	-
26	REAR DOOR SCUFF PLATE INSIDE LH	67918F	-	-	-
27	REAR UNDER SIDE COVER LH	76974E	-	-	-
28	REAR DOOR SCUFF PLATE INSIDE RH	67917F	-	-	-
29	REAR UNDER SIDE COVER RH	76973E	-	-	-
30	REAR UNDER COVER	76917F	-	-	-
31	REAR SEAT CUSHION LEG SUB-ASSEMBLY	71033	-	-	-

*A	for Type A	*B	for Type B
●	Non-reusable part	-	-

Procedure		Part Name Code
32	NO. 1 HV BATTERY COVER PANEL RH	G92N4A	-	-
33	UPPER HV BATTERY COVER SUB-ASSEMBLY	-	-	-
34	BATTERY ECU ASSEMBLY	89890A	-	-

Battery Cover Lock Striker

PROCEDURE

1. PRECAUTION

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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 Toyota Prius 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 ignition switch on (READY) and wait for 5 minutes or more.

(5) Turn the ignition 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 ignition 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

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4. REMOVE FRONT WIPER ARM HEAD CAP

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5. REMOVE SHIELD CAP (for M20A-FXS)

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6. REMOVE FRONT WIPER ARM AND BLADE ASSEMBLY LH

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7. REMOVE FRONT WIPER ARM AND BLADE ASSEMBLY RH

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8. REMOVE WINDSHIELD LOWER OUTSIDE MOULDING LH

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9. REMOVE WINDSHIELD LOWER OUTSIDE MOULDING RH

(a) Use the same procedure as for the LH side.

10. REMOVE COWL WATER EXTRACT SHIELD LH

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11. REMOVE COWL WATER EXTRACT SHIELD RH

(a) Use the same procedure as for the LH side.

12. REMOVE COWL TOP VENTILATOR LOUVER SUB-ASSEMBLY

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13. CHECK TERMINAL VOLTAGE

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14. INSTALL COWL TOP VENTILATOR LOUVER SUB-ASSEMBLY

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15. INSTALL COWL WATER EXTRACT SHIELD RH

16. INSTALL COWL WATER EXTRACT SHIELD LH

17. INSTALL WINDSHIELD LOWER OUTSIDE MOULDING LH

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18. INSTALL WINDSHIELD LOWER OUTSIDE MOULDING RH

(a) Use the same procedure as for the LH side.

19. INSTALL FRONT WIPER ARM AND BLADE ASSEMBLY LH

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20. INSTALL FRONT WIPER ARM AND BLADE ASSEMBLY RH

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21. INSTALL SHIELD CAP (for M20A-FXS)

22. INSTALL FRONT WIPER ARM HEAD CAP

23. DISCONNECT REAR CENTER SEAT OUTER BELT ASSEMBLY

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24. REMOVE REAR SEAT CUSHION ASSEMBLY

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25. REMOVE REAR SEAT CUSHION LOCK HOOK

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26. REMOVE REAR DOOR SCUFF PLATE INSIDE LH

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27. REMOVE REAR UNDER SIDE COVER LH

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28. REMOVE REAR DOOR SCUFF PLATE INSIDE RH

(a) Use the same procedure as for the LH side.

29. REMOVE REAR UNDER SIDE COVER RH

(a) Use the same procedure as for the LH side.

30. REMOVE REAR UNDER COVER

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31. REMOVE REAR SEAT CUSHION LEG SUB-ASSEMBLY

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32. REMOVE NO. 1 HV BATTERY COVER PANEL RH

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33. REMOVE UPPER HV BATTERY COVER SUB-ASSEMBLY

CAUTION:

Be sure to wear insulated gloves and protective goggles.

34. REMOVE BATTERY ECU ASSEMBLY

CAUTION:

Be sure to wear insulated gloves and protective goggles.

NOTICE:

Insulate each disconnected high-voltage connector with insulating tape. Wrap the connector from the wire harness side to the end of the connector.
If the battery ECU assembly has been struck or dropped, replace it.

(1) Disconnect the 3 battery ECU assembly connectors.

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

Installation

INSTALLATION

CAUTION / NOTICE / HINT

NOTICE:

This procedure includes the installation of small-head bolts. Refer to Small-Head Bolts of Basic Repair Hint to identify the small-head bolts.

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CAUTION / NOTICE / HINT

COMPONENTS (INSTALLATION)

Procedure		Part Name Code
1	BATTERY ECU ASSEMBLY	89890A	-	-
2	UPPER HV BATTERY COVER SUB-ASSEMBLY	-	-	-
3	NO. 1 HV BATTERY COVER PANEL RH	G92N4A	-	-

*1	Battery Cover Lock Striker	-	-
	Nm (kgfcm, ft.*lbf): Specified torque	-	-

Procedure		Part Name Code
4	REAR SEAT CUSHION LEG SUB-ASSEMBLY	71033		-	-
5	REAR UNDER COVER	76971F	-	-	-
6	REAR UNDER SIDE COVER LH	76974E	-	-	-
7	REAR DOOR SCUFF PLATE INSIDE LH	67918F	-	-	-
8	REAR UNDER SIDE COVER RH	76973E	-	-	-
9	REAR DOOR SCUFF PLATE INSIDE RH	67917F	-	-	-
10	REAR SEAT CUSHION LOCK HOOK	72693	-	-	-
11	REAR SEAT CUSHION ASSEMBLY	-		-	-
12	REAR CENTER SEAT OUTER BELT ASSEMBLY	73350C	-	-	-

*A	for Type A	*B	for Type B
	Tightening torque for "Major areas involving basic Toyota Prius vehicle performance such as moving/turning/stopping" : Nm (kgfcm, ft.*lbf)	●	Non-reusable part