Last Modified: 05-13-2024 6.11:8.1.0 Doc ID: RM1000000026JDC
Model Year Start: 2023 Model: Corolla Hatchback Prod Date Range: [09/2022 - 11/2022]
Title: M20A-FKS (ENGINE CONTROL): SFI SYSTEM: ECM Power Source Circuit; 2023 MY Corolla Corolla Hatchback [09/2022 - 11/2022]

ECM Power Source Circuit

DESCRIPTION

When the ignition switch is turned to ON, the battery voltage is applied to the IGSW*1 or IGP*2 terminal of the ECM. The output signal from the MREL terminal of the ECM causes current to flow to the coil of the No. 1 integration relay (EFI-MAIN relay)*1 or EFI-MAIN NO. 1*2, closing the contacts of the EFI-MAIN relay*1 or EFI-MAIN NO. 1 relay*2 and supplying power to terminals +B and +B2 of the ECM.

  • *1: for TMMMS Made
  • *2: for TMC Made

WIRING DIAGRAM

for TMMMS Made
for TMC Made
for TMC Made

CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses for circuits related to this system before performing the following procedure.

PROCEDURE

1.

CHECK VEHICLE SPECIFICATION

(a) Check the vehicle specification

Result

Proceed to

for TMMMS Made

A

for TMC Made

B

B

GO TO STEP 11

A

2.

CHECK HARNESS AND CONNECTOR (POWER SOURCE OF NO. 1 INTEGRATION RELAY)

(a) Disconnect the No. 1 integration relay connector.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

1A-10 - Body ground

Always

11 to 14 V

1B-3 - Body ground

Always

11 to 14 V

1B-5 - Body ground

Always

11 to 14 V

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - NO. 1 INTEGRATION RELAY)

OK

3.

INSPECT NO. 1 INTEGRATION RELAY (EFI-MAIN RELAY, IG2 NO. 1 RELAY)

(a) Inspect the No. 1 integration relay (EFI-MAIN relay, IG2 NO. 1 relay).

Click here 2023 MY Corolla Corolla Hatchback Corolla HV GR Corolla [09/2022 - 11/2022]; POWER DISTRIBUTION: INTEGRATION RELAY: INSPECTION

NG

REPLACE NO. 1 INTEGRATION RELAY

OK

4.

CHECK HARNESS AND CONNECTOR (NO. 1 INTEGRATION RELAY - ECM)

(a) Disconnect the No. 1 integration relay connector.

(b) Disconnect the ECM connector.

(c) Remove the EFI-MAIN NO. 2 relay and EFI-MAIN NO. 3 relay from the No. 1 engine room relay block and No. 1 junction block assembly.

HINT:

Remove the EFI-MAIN NO. 2 and EFI-MAIN NO. 3 relays connected between the checked terminals as the coil inside the relay influences the measurement value.

(d) Remove the VVT relay from No. 2 relay block assembly.

HINT:

Remove the VVT relay connected between the checked terminals as the coil inside the relay influences the measurement value.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

1A-9 - A47-2 (IGSW)

Always

Below 1 Ω

1B-6 - A47-15 (MREL)

Always

Below 1 Ω

1B-4 - A47-9 (+B)

Always

Below 1 Ω

1B-4 - A47-35 (+B2)

Always

Below 1 Ω

1A-9 or A47-2 (IGSW) - Body ground and other terminals

Always

10 kΩ or higher

1B-6 or A47-15 (MREL) - Body ground and other terminals

Always

10 kΩ or higher

1B-4 or A47-9 (+B) - Body ground and other terminals

Always

10 kΩ or higher

1B-4 or A47-35 (+B2) - Body ground and other terminals

Always

10 kΩ or higher

HINT:

If a short is detected in any of the above circuits, there may be a malfunction in the circuit of a connected ECU.

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

5.

CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND)

(a) Disconnect the ECM connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A47-10 (E1) - Body ground

Always

Below 1 Ω

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

6.

CHECK HARNESS AND CONNECTOR (NO. 1 INTEGRATION RELAY - BODY GROUND)

(a) Disconnect the No. 1 integration relay connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

1A-8 - Body ground

Always

Below 1 Ω

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

7.

CHECK TERMINAL VOLTAGE (IGSW TERMINAL VOLTAGE)

*a

Front view of wire harness connector

(to ECM)

(a) Disconnect the ECM connector.

(b) Turn the ignition switch to ON.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

A47-2 (IGSW) - Body ground

Ignition switch ON

11 to 14 V

Result

Proceed to

OK

A

NG (w/ Smart Key System)

B

NG (w/o Smart Key System)

C

A

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

C

GO TO STEP 9

B

8.

CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - NO. 1 INTEGRATION RELAY)

(a) Disconnect the certification ECU (smart key ECU assembly) connector.

(b) Disconnect the No. 1 integration relay connector.

(c) Disconnect the instrument panel junction block assembly 4F connector.

HINT:

Disconnect the IG1-NO. 1, IG1-NO. 2 and IG2-NO. 2 relays connected between the checked terminals as the coil inside the relay influences the measurement value.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

I1-15 (IG1D) - 1A-7

Always

Below 1 Ω

I1-15 (IG1D) or 1A-7 - Body ground and other terminals

Always

10 kΩ or higher

OK

GO TO SMART KEY SYSTEM

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

9.

INSPECT IGNITION OR STARTER SWITCH ASSEMBLY

(a) Inspect the ignition or starter switch assembly.

Click here 2020 - 2025 MY Corolla Corolla Hatchback [01/2019 -        ]; M20A-FKS (STARTING): IGNITION SWITCH: INSPECTION

NG

REPLACE IGNITION OR STARTER SWITCH ASSEMBLY

OK

10.

CHECK HARNESS AND CONNECTOR (IGNITION OR STARTER SWITCH ASSEMBLY - NO. 1 INTEGRATION RELAY)

(a) Disconnect the ignition or starter switch assembly connector.

(b) Disconnect the No. 1 integration relay connector.

(c) Disconnect the instrument panel junction block assembly 4F connector.

HINT:

Disconnect the IG1-NO. 1, IG1-NO. 2 and IG2-NO. 2 relays connected between the checked terminals as the coil inside the relay influences the measurement value.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

I12-8 (IG1) - 1A-7

Always

Below 1 Ω

I12-8 (IG1) or 1A-7 - Body ground and other terminals

Always

10 kΩ or higher

OK

REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - IGNITION OR STARTER SWITCH ASSEMBLY)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

11.

CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND)

(a) Disconnect the ECM connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A47-10 (E1) - Body ground

Always

Below 1 Ω

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

12.

CHECK TERMINAL VOLTAGE (IGP TERMINAL VOLTAGE)

(a) Disconnect the ECM connector.

(b) Turn the ignition switch to ON.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

A47-2 (IGP) - Body ground

Ignition switch ON

11 to 14 V

*a

Front view of wire harness connector

(to ECM)

NG

GO TO STEP 16

OK

13.

INSPECT EFI-MAIN NO. 1 RELAY

Click here 2023 MY Corolla Corolla Hatchback [09/2022 - 11/2022]; M20A-FKS (ENGINE CONTROL): RELAY: ON-VEHICLE INSPECTION

NG

REPLACE EFI-MAIN NO. 1 RELAY

OK

14.

CHECK HARNESS AND CONNECTOR (EFI-MAIN NO. 1 RELAY - ECM)

(a) Disconnect the ECM connector.

(b) Remove the EFI-MAIN NO. 1 relay, EFI-MAIN NO. 3 relay and EDU relay from the No. 1 engine room relay block and No. 1 junction block assembly.

HINT:

Remove the EFI-MAIN NO. 2 VVT, and EFI-MAIN NO. 3 relays connected between the checked terminals as the coil inside the relay influences the measurement value.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

1(EFI-MAIN NO.1 relay) - A47-15 (MREL)

Always

Below 1 Ω

3(EFI-MAIN NO.1 relay) - A47-9 (+B)

Always

Below 1 Ω

3(EFI-MAIN NO.1 relay) - A47-35 (+B2)

Always

Below 1 Ω

1(EFI-MAIN NO.1 relay) or A47-15 (MREL) - Body ground and other terminals

Always

10 kΩ or higher

1(EFI-MAIN NO.1 relay), A47-15(MREL), A47-9 (+B) or A47-35 (+B2) - Body ground and other terminals

Always

10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

15.

CHECK TERMINAL VOLTAGE (POWER SOURCE OF EFI-MAIN NO. 1 RELAY)

*1

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

*2

EFI-MAIN NO. 1 Relay

(a) Remove the EFI-MAIN NO. 1 relay from the No. 1 engine room relay block and No. 1 junction block assembly.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

2(EFI-MAIN NO. 1 relay) - Body ground

Always

11 to 14 V

5(EFI-MAIN NO. 1 relay) - Body ground

Always

11 to 14 V

OK

REPLACE ECM

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - EFI-MAIN NO. 1 RELAY)

16.

INSPECT IGP-MAIN RELAY

Click here 2023 MY Corolla Corolla Hatchback [09/2022 - 11/2022]; M20A-FKS (ENGINE CONTROL): RELAY: ON-VEHICLE INSPECTION

NG

REPLACE IGP-MAIN RELAY

OK

17.

CHECK HARNESS AND CONNECTOR (IGP-MAIN RELAY - ECM)

(a) Disconnect the ECM connector.

(b) Remove the IGP-MAIN 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.

Standard Resistance:

Tester Connection

Condition

Specified Condition

3(IGP-MAIN relay) - A47-2 (IGP)

Always

Below 1 Ω

3(IGP-MAIN relay) or A47-2 (IGP) - Body ground and other terminals

Always

10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

18.

CHECK HARNESS AND CONNECTOR (POWER SOURCE VOLTAGE OF IGP-MAIN RELAY)

*1

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

*2

IGP-MAIN Relay

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

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

5(IGP-MAIN relay) - Body ground

Always

11 to 14 V

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - IGP-MAIN RELAY)

OK

19.

CHECK HARNESS AND CONNECTOR (IGP RELAY - BODY GROUND)

(a) Remove the IGP-MAIN 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

1(IGP-MAIN relay) - Body ground

Always

Below 1 Ω

Result

Proceed to

OK (w/ Smart Key System)

A

OK (w/o Smart Key System)

B

NG

C

B

GO TO STEP 21

C

REPAIR OR REPLACE HARNESS OR CONNECTOR

A

20.

CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - IGP-MAIN RELAY)

(a) Disconnect the certification ECU (smart key ECU assembly) connector.

(b) Remove the IGP-MAIN 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.

Standard Resistance:

Tester Connection

Condition

Specified Condition

O175-24 (IGPD) - 2(IGP-MAIN relay)

Always

Below 1 Ω

O175-24 (IGPD) or 2(IGP-MAIN relay) - Body ground and other terminals

Always

10 kΩ or higher

OK

GO TO SMART KEY SYSTEM

for TMMMS Made: Click here 2023 MY Corolla Corolla Hatchback GR Corolla [09/2022 - 11/2022]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function (Gasoline Model, except TMMMS Made)): HOW TO PROCEED WITH TROUBLESHOOTING

for TMC Made: Click here 2023 MY Corolla Corolla Hatchback GR Corolla [09/2022 - 11/2022]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function (Gasoline Model, except TMMMS Made)): HOW TO PROCEED WITH TROUBLESHOOTING

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

21.

INSPECT IGNITION OR STARTER SWITCH ASSEMBLY

(a) Inspect the ignition or starter switch assembly.

Click here 2020 - 2025 MY Corolla Corolla Hatchback [01/2019 -        ]; M20A-FKS (STARTING): IGNITION SWITCH: INSPECTION

NG

REPLACE IGNITION OR STARTER SWITCH ASSEMBLY

OK

22.

CHECK HARNESS AND CONNECTOR (IGNITION OR STARTER SWITCH ASSEMBLY - IGP-MAIN RELAY)

(a) Disconnect the ignition or starter switch assembly connector.

(b) Remove the IGP-MAIN 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.

Standard Resistance:

Tester Connection

Condition

Specified Condition

I12-8 (IG1) - 2 (IGP-MAIN relay)

Always

Below 1 Ω

I12-8 (IG1) or 2 (IGP-MAIN relay) - Body ground and other terminals

Always

10 kΩ or higher

OK

REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - IGNITION OR STARTER SWITCH ASSEMBLY)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR