Last Modified: 05-13-2024 6.11:8.1.0 Doc ID: RM100000001N40H
Model Year Start: 2021 Model: Corolla Prod Date Range: [04/2020 - 09/2022]
Title: HYBRID / BATTERY CONTROL: HYBRID CONTROL SYSTEM (for LITHIUM-ION BATTERY with P610): ECU Power Source Circuit; 2021 - 2022 MY Corolla Corolla HV [04/2020 - 09/2022]

ECU Power Source Circuit

DESCRIPTION

If the power switch is on (IG), the hybrid vehicle control ECU applies current to the MREL terminal to turn the IGCT relay on. This supplies power to the +B1 and +B2 terminals.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

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 2021 - 2022 MY Corolla Corolla Hatchback Corolla HV GR Corolla [04/2020 - 09/2022]; INTRODUCTION: REPAIR INSTRUCTION: INITIALIZATION

PROCEDURE

1.

CHECK HYBRID VEHICLE CONTROL ECU (+B1, +B2 VOLTAGE)

(a) Turn the power switch on (IG).

(b) Measure the voltage according to the value(s) in the table below.

*a

Component with harness connected

(Hybrid Vehicle Control ECU)

-

-

Standard Voltage:

Tester Connection

Condition

Specified Condition

A57-11 (+B1) - Body ground

Power switch on (IG)

11 to 14 V

I3-1 (+B2) - Body ground

Power switch on (IG)

11 to 14 V

(c) Turn the power switch off.

NG

GO TO STEP 3

OK

2.

CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - BODY GROUND)

(a) Disconnect the I2 and I3 hybrid vehicle control ECU connectors.

(b) Measure the resistance according to the value(s) in the table below.

*a

Front view of wire harness connector

(to Hybrid Vehicle Control ECU)

-

-

Standard Resistance:

Tester Connection

Condition

Specified Condition

I3-3 (E1) - Body ground

Always

Below 1 Ω

I2-12 (E01) - Body ground

Always

Below 1 Ω

I2-11 (E02) - Body ground

Always

Below 1 Ω

I2-34 (E12) - Body ground

Always

Below 1 Ω

(c) Reconnect the I2 and I3 hybrid vehicle control ECU connectors.

OK

GO TO PROBLEM SYMPTOMS TABLE

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

3.

CHECK HYBRID VEHICLE CONTROL ECU (MREL VOLTAGE)

(a) Turn the power switch on (IG).

(b) Measure the voltage according to the value(s) in the table below.

*a

Component with harness connected

(Hybrid Vehicle Control ECU)

-

-

Standard Voltage:

Tester Connection

Condition

Specified Condition

A57-5 (MREL) - Body ground

Power switch on (IG)

11 to 14 V

(c) Turn the power switch off.

NG

REPLACE HYBRID VEHICLE CONTROL ECU

OK

4.

CHECK FUSE (PM-IGCT)

(a) Remove the PM-IGCT fuse from the No. 1 engine room relay block and No. 1 junction block assembly.

*1

No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly

*2

PM-IGCT Fuse

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

PM-IGCT fuse

Always

Below 1 Ω

(c) Install the PM-IGCT fuse.

NG

GO TO STEP 11

OK

5.

CHECK FUSE (IGCT-IG)

(a) Remove the IGCT-IG fuse from the No. 1 engine room relay block and No. 1 junction block assembly.

*1

No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly

*2

IGCT-IG Fuse

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

IGCT-IG fuse

Always

Below 1 Ω

(c) Install the IGCT-IG fuse.

NG

GO TO STEP 12

OK

6.

INSPECT RELAY (IGCT)

(a) Remove the IGCT relay from the No. 1 engine room relay block and No. 1 junction block assembly.

*1

No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly

*2

IGCT Relay

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

3 - 5

Auxiliary battery voltage not applied between terminals 1 and 2

10 kΩ or higher

Auxiliary battery voltage applied between terminals 1 and 2

Below 1 Ω

*1

IGCT Relay

(c) Install the IGCT relay.

NG

REPLACE RELAY (IGCT)

OK

7.

CHECK HARNESS AND CONNECTOR (NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY - HYBRID VEHICLE CONTROL ECU)

(a) Disconnect the A57 and I3 hybrid vehicle control ECU connectors.

(b) Remove the PM-IGCT fuse from the No. 1 engine room relay block and No. 1 junction block assembly.

(c) 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

PM-IGCT Fuse Holder

*a

Front view of wire harness connector

(to Hybrid Vehicle Control ECU)

-

-

Standard Resistance:

Tester Connection

Condition

Specified Condition

A57-11 (+B1) - 2 (PM-IGCT fuse holder)

Always

Below 1 Ω

I3-1 (+B2) - 2 (PM-IGCT fuse holder)

Always

Below 1 Ω

(d) Install the PM-IGCT fuse.

(e) Reconnect the A57 and I3 hybrid vehicle control ECU connectors.

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

8.

CHECK HARNESS AND CONNECTOR (NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY)

(a) Remove the IGCT-IG fuse, PM-IGCT 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:

Tester Connection

Condition

Specified Condition

3 (IGCT relay holder) - 2 (IGCT-IG fuse holder)

Always

Below 1 Ω

5 (IGCT relay holder) - 1 (PM-IGCT fuse holder)

Always

Below 1 Ω

*1

No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly

*2

PM-IGCT Fuse Holder

*3

IGCT-IG Fuse Holder

*4

IGCT Relay Holder

(c) Install the IGCT-IG fuse, PM-IGCT fuse and IGCT relay.

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

9.

CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY)

(a) Disconnect the A57 hybrid vehicle control ECU connector.

(b) Remove the IGCT relay from the No. 1 engine room relay block and No. 1 junction block assembly.

(c) 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 Relay Holder

*a

Front view of wire harness connector

(to Hybrid Vehicle Control ECU)

-

-

Standard Resistance:

Tester Connection

Condition

Specified Condition

A57-5 (MREL) - 1 (IGCT relay holder)

Always

Below 1 Ω

A57-5 (MREL) or 1 (IGCT relay holder) - Body ground and other terminals

Always

10 kΩ or higher

(d) Install the IGCT relay.

(e) Reconnect the A57 hybrid vehicle control ECU connector.

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

10.

CHECK HARNESS AND CONNECTOR (NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY - BODY GROUND)

(a) Remove the 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:

Tester Connection

Condition

Specified Condition

2 (IGCT relay holder) - Body ground

Always

Below 1 Ω

*1

No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly

*2

IGCT Relay Holder

(c) Install the IGCT relay.

OK

CHECK FOR INTERMITTENT PROBLEMS

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

11.

CHECK HARNESS AND CONNECTOR (NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY - HYBRID VEHICLE CONTROL ECU)

(a) Remove the PM-IGCT fuse from the No. 1 engine room relay block and No. 1 junction block assembly.

(b) Disconnect the A57 and I3 hybrid vehicle control ECU connectors.

(c) 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

PM-IGCT Fuse Holder

*a

Front view of wire harness connector

(to Hybrid Vehicle Control ECU)

-

-

Standard Resistance:

Tester Connection

Condition

Specified Condition

A57-11 (+B1) or 2 (PM-IGCT fuse holder) - Body ground and other terminals

Always

10 kΩ or higher

I3-1 (+B2) or 2 (PM-IGCT fuse holder) - Body ground and other terminals

Always

10 kΩ or higher

(d) Reconnect the A57 and I3 hybrid vehicle control ECU connectors.

(e) Install the PM-IGCT fuse.

OK

REPLACE FUSE (PM-IGCT)

NG

GO TO STEP 13

12.

CHECK HARNESS AND CONNECTOR (NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY)

(a) Remove the IGCT-IG fuse, PM-IGCT 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:

Tester Connection

Condition

Specified Condition

3 (IGCT relay holder) or 2 (IGCT-IG fuse holder) - Body ground and other terminals

Always

10 kΩ or higher

5 (IGCT relay holder) or 1 (PM-IGCT fuse holder) - Body ground and other terminals

Always

10 kΩ or higher

*1

No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly

*2

PM-IGCT Fuse Holder

*3

IGCT-IG Fuse Holder

*4

IGCT Relay Holder

(c) Install the IGCT-IG fuse, PM-IGCT fuse and IGCT relay.

OK

REPLACE RELAY (IGCT-IG)

NG

GO TO STEP 14

13.

REPAIR OR REPLACE HARNESS OR CONNECTOR

NEXT

REPLACE FUSE (PM-IGCT)

14.

REPAIR OR REPLACE HARNESS OR CONNECTOR

NEXT

REPLACE FUSE (IGCT-IG)