| Last Modified: 06-05-2026 | 6.11:8.1.0 | Doc ID: RM100000001N360 |
| Model Year Start: 2021 | Model: Corolla HV | Prod Date Range: [04/2020 - 09/2022] |
| Title: HYBRID / BATTERY CONTROL: HYBRID BATTERY SYSTEM (for LITHIUM-ION BATTERY with P610): ECU Power Source Circuit; 2021 - 2022 MY Corolla HV [04/2020 - 09/2022] | ||
|
ECU Power Source Circuit |
DESCRIPTION
If the power switch is on (IG), the battery ECU assembly applies current to the MREL terminal to turn the IGCT relay on. This supplies power to the IGCT terminals.
WIRING DIAGRAM
CAUTION / NOTICE / HINT
CAUTION:
-
Before the following operations are conducted, take precautions to prevent electric shock by turning the power switch off, wearing insulated gloves, and removing the service plug grip from HV battery.
- Inspecting the high-voltage system
- Disconnecting the low voltage connector of the inverter with converter assembly
- Disconnecting the low voltage connector of the HV battery
-
To prevent electric shock, make sure to remove the service plug grip to cut off the high voltage circuit before servicing the vehicle.
-
After removing the service plug grip from the HV battery, put it in your pocket to prevent other technicians from accidentally reconnecting it while you are working on the high-voltage system.
-
After removing the service plug grip, wait for at least 10 minutes before touching any of the high-voltage connectors or terminals. After waiting for 10 minutes, check the voltage at the terminals in the inspection point in the inverter with converter assembly. The voltage should be 0 V before beginning work.
*a
Without waiting for 10 minutes
Click here
![2021 - 2022 MY Corolla HV [04/2020 - 09/2022]; HYBRID / BATTERY CONTROL: HYBRID BATTERY SYSTEM (for LITHIUM-ION BATTERY with P610): PRECAUTION](/t3Portal/stylegraphics/info.gif)
HINT:
Waiting for at least 10 minutes is required to discharge the high-voltage capacitor inside the inverter with converter assembly.
NOTICE:
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.
Click here
PROCEDURE
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1. |
CHECK BATTERY ECU ASSEMBLY (IGCT VOLTAGE) |
CAUTION:
Be sure to wear insulated gloves and protective goggles.
(a) Check that the service plug grip is not installed.
NOTICE:
After removing the service plug grip, do not turn the power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.
(b) Remove the No. 1 HV battery protector.
Click here
(c) Connect the cable to the negative (-) auxiliary battery terminal.
(d) Turn the power switch on (IG).
|
(e) Measure the voltage according to the value(s) in the table below. Standard Voltage
NOTICE: Turning the power switch on (IG) with the service plug grip removed causes other DTCs to be stored. Clear the DTCs after performing this inspection. |
|
(f) Turn the power switch off.
(g) Disconnect the cable from the negative (-) auxiliary battery terminal.
(h) Install the No. 1 HV battery protector.
| NG |
|
|
|
2. |
CHECK HARNESS AND CONNECTOR (BATTERY ECU ASSEMBLY - BODY GROUND) |
CAUTION:
Be sure to wear insulated gloves and protective goggles.
(a) Check that the service plug grip is not installed.
NOTICE:
After removing the service plug grip, do not turn the power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.
(b) Remove the No. 1 HV battery protector.
Click here
(c) Disconnect the z28 battery ECU assembly connector.
NOTICE:
Before disconnecting the connector, check that it is not loose or disconnected.
|
(d) Measure the resistance according to the value(s) in the table below. Standard Resistance
|
|
(e) Reconnect the z28 battery ECU assembly connector.
(f) Install the No. 1 HV battery protector.
| OK |
|
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
3. |
CHECK FUSE (IGCT NO. 2) |
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(a) Remove the IGCT NO. 2 fuse from the No. 1 engine room relay block and No. 1 junction block assembly. |
|
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
IGCT NO. 2 fuse terminals - Body ground |
Always |
Below 1 Ω |
(c) Install the IGCT NO. 2 fuse.
| NG |
|
|
|
4. |
CHECK HARNESS AND CONNECTOR (IGCT NO. 2 FUSE - BATTERY ECU ASSEMBLY) |
CAUTION:
Be sure to wear insulated gloves and protective goggles.
(a) Check that the service plug grip is not installed.
NOTICE:
After removing the service plug grip, do not turn the power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.
(b) Remove the No. 1 HV battery protector.
Click here
(c) Disconnect the z28 battery ECU assembly connector.
NOTICE:
Before disconnecting the connector, check that it is not loose or disconnected.
|
(d) Remove the IGCT NO. 2 fuse from the No. 1 engine room relay block and No. 1 junction block assembly. |
|
(e) Measure the resistance according to the value(s) in the table below.
|
*1 |
No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly |
*2 |
IGCT NO. 2 Fuse Holder |
|
*a |
Rear view of wire harness connector (to Battery ECU Assembly) |
- |
- |
Standard Resistance
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
z28-16 (IGCT) - 2 (IGCT NO. 2 fuse holder) |
Always |
Below 1 Ω |
(f) Install the IGCT NO. 2 fuse.
(g) Reconnect the z28 battery ECU assembly connector.
(h) Install the No. 1 HV battery protector.
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
5. |
CHECK HARNESS AND CONNECTOR (IGCT RELAY - IGCT NO. 2 FUSE) |
|
(a) Remove the IGCT NO. 2 fuse and IGCT relay from the No. 1 engine room relay block and No. 1 junction block assembly. |
|
|
(b) Measure the resistance according to the value(s) in the table below. Standard Resistance
|
|
(c) Install the IGCT NO. 2 fuse and IGCT relay.
| OK |
|
CHECK ECU Power Source Circuit (HYBRID CONTROL SYSTEM (for LITHIUM-ION BATTERY)) |
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
6. |
CHECK HARNESS AND CONNECTOR (IGCT NO. 2 FUSE - BATTERY ECU ASSEMBLY) |
CAUTION:
Be sure to wear insulated gloves and protective goggles.
(a) Check that the service plug grip is not installed.
NOTICE:
After removing the service plug grip, do not turn the power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.
(b) Remove the No. 1 HV battery protector.
Click here
(c) Disconnect the z28 battery ECU assembly connector.
NOTICE:
Before disconnecting the connector, check that it is not loose or disconnected.
|
(d) Remove the IGCT NO. 2 fuse from the No. 1 engine room relay block and No. 1 junction block assembly. |
|
(e) Measure the resistance according to the value(s) in the table below.
|
*1 |
No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly |
*2 |
IGCT NO. 2 Fuse Holder |
|
*a |
Rear view of wire harness connector (to Battery ECU Assembly) |
- |
- |
Standard Resistance
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
z28-16 (IGCT) or 2 (IGCT NO. 2 fuse holder) - Body ground and other terminals |
Always |
Below 1 Ω |
(f) Install the IGCT NO. 2 fuse.
(g) Reconnect the z28 battery ECU assembly connector.
(h) Install the No. 1 HV battery protector.
| OK |
|
REPLACE FUSE (IGCT NO. 2) |
|
|
7. |
REPAIR OR REPLACE HARNESS OR CONNECTOR |
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