Last Modified: 05-13-2024 6.11:8.1.0 Doc ID: RM100000002B3NE
Model Year Start: 2023 Model: Corolla Hatchback Prod Date Range: [03/2023 -           ]
Title: M20A-FKS (ENGINE CONTROL): SFI SYSTEM: Starter Signal Circuit; 2023 - 2025 MY Corolla Corolla Hatchback [03/2023 -        ]

Starter Signal Circuit

DESCRIPTION

for K120

While the engine is being cranked, current flows from terminal STAR of the certification ECU (smart key ECU assembly)*2 to the park/neutral position switch assembly and to terminal STA of the ECM (STA signal).

for K121

While the engine is being cranked, current flows from terminal ST1 of the ignition or starter switch assembly*1 or terminal STAR of the certification ECU (smart key ECU assembly)*2 to terminal STA of the ECM (STA signal).

*1: w/o Smart Key System

*2: w/ Smart Key System

WIRING DIAGRAM

Refer to DTC P061512.

Click here 2023 - 2025 MY Corolla Corolla Hatchback [03/2023 -        ]; M20A-FKS (ENGINE CONTROL): SFI SYSTEM: P061512; Starter Relay Circuit Short to Battery+

CAUTION / NOTICE / HINT

NOTICE:

  • Inspect the fuses for circuits related to this system before performing the following procedure.
  • After the ignition switch is turned off, there may be a waiting time before disconnecting the negative (-) 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

  • When disconnecting and reconnecting the battery.

    HINT:

    When disconnecting and reconnecting the battery, there is an automatic learning function that completes learning when the respective system is used.

    Click here 2023 - 2025 MY Corolla Corolla Hatchback Corolla HV GR Corolla [11/2022 -        ]; SETUP: WHEN DISCONNECTING OR RECONNECTING BATTERY TERMINAL: AUTOMATIC LEARNING CHART

PROCEDURE

1.

CHECK WHETHER ENGINE CAN BE CRANKED

(a) Check if the engine can be cranked.

Result

Proceed to

Engine cannot be cranked

A

Engine can be cranked

B

B

GO TO STEP 21

A

2.

READ VALUE USING TECHSTREAM (STARTER SW)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Data List / Starter SW.

Powertrain > Engine > Data List

Tester Display

Starter SW

(e) Check the value displayed on the Techstream when the ignition switch is turned to the ON and START positions.

OK:

Condition

Techstream Display (Starter SW)

Ignition switch ON

OFF

Engine started

ON

Result

Proceed to

OK

A

NG (for K120)

B

NG (for K121 with Smart Key System)

C

NG (for K121 without Smart Key System)

D

B

GO TO STEP 11

C

GO TO STEP 14

D

GO TO STEP 15

A

3.

INSPECT ST RELAY

(a) Inspect the ST relay.

Click here 2023 - 2025 MY Corolla Corolla Hatchback [03/2023 -        ]; M20A-FKS (STARTING): RELAY: INSPECTION

NG

REPLACE ST RELAY

OK

4.

INSPECT STARTER ASSEMBLY

(a) Inspect the starter assembly.

Click here 2019 - 2025 MY Corolla Corolla Hatchback [06/2018 -        ]; M20A-FKS (STARTING): STARTER: INSPECTION

NG

REPLACE STARTER ASSEMBLY

OK

5.

CHECK HARNESS AND CONNECTOR (ST RELAY - STARTER ASSEMBLY)

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

(b) Disconnect the starter assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

3 (ST relay) - C82-1 (ST)

Always

Below 1 Ω

3 (ST relay) or C82-1 (ST) - Body ground and other terminals

Always

10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

6.

CHECK TERMINAL VOLTAGE (BATTERY - STARTER ASSEMBLY)

(a) Disconnect the cable from the negative (-) battery terminal.

(b) Disconnect the cable from the positive (+) battery terminal.

(c) Disconnect the starter assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

Positive (+) battery terminal - C111-1 (B)

Always

Below 1 Ω

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

7.

CHECK TERMINAL VOLTAGE (POWER SOURCE OF ST RELAY)

*1

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

*2

ST Relay

(a) Remove the ST 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 (ST relay) - Body ground

Always

11 to 14 V

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - ST RELAY)

OK

8.

CHECK HARNESS AND CONNECTOR (ST RELAY - BODY GROUND)

(a) Remove the ST 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 (ST relay) - Body ground

Always

Below 1 Ω

Result

Proceed to

OK (for K120)

A

OK (for K121)

B

NG

C

B

GO TO STEP 10

C

REPAIR OR REPLACE HARNESS OR CONNECTOR

A

9.

CHECK HARNESS AND CONNECTOR (ST RELAY - PARK/NEUTRAL POSITION SWITCH ASSEMBLY)

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

(b) Disconnect the park/neutral position switch assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

1 (ST relay) - C62-5 (L)

Always

Below 1 Ω

OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

10.

CHECK HARNESS AND CONNECTOR (ST RELAY - ECM)

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

(b) Disconnect the ECM connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

2 (ST relay holder) - A178-18 (STA)

Always

Below 1 Ω

OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

11.

INSPECT PARK/NEUTRAL POSITION SWITCH ASSEMBLY

(a) Inspect the park/neutral position switch assembly.

Click here 2019 - 2025 MY Corolla Corolla Hatchback [06/2018 -        ]; K120 / K121 (CVT): K120 PARK / NEUTRAL POSITION SWITCH: INSPECTION

NG

REPLACE PARK/NEUTRAL POSITION SWITCH ASSEMBLY

OK

12.

CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - PARK/NEUTRAL POSITION SWITCH ASSEMBLY - ECM)

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

(b) Disconnect the park/neutral position switch assembly connector.

(c) Disconnect the ECM connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

O175-10 (STAR) - C62-4 (B)

Always

Below 1 Ω

O175-10 (STAR) - A47-23 (NSW)

Always

Below 1 Ω

O175-10 (STAR), C62-4 (B) or A47-23 (NSW) - Body ground and other terminals

Always

10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

13.

CHECK HARNESS AND CONNECTOR (STA SIGNAL CIRCUIT)

(a) Disconnect the park/neutral position switch assembly connector.

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

(c) Disconnect the ECM connector.

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

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

O175-1 (STA) - 1 (ST relay)

Always

Below 1 Ω

C62-5 (L) - 1 (ST relay)

Always

Below 1 Ω

A47-30 (STA) - 1 (ST relay)

Always

Below 1 Ω

O175-1 (STA), 1 (ST relay), C62-5 (L) and A47-30 (STA) - Body ground and other terminals

Always

10 kΩ or higher

OK

GO TO SMART KEY SYSTEM

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

14.

CHECK HARNESS AND CONNECTOR (STA SIGNAL CIRCUIT)

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

(b) Disconnect the ECM connector.

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

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A178-18 (STA) - O175-10 (STAR)

Always

Below 1 Ω

A178-18 (STA), O175-10 (STAR) and 1 (ST relay) - Body ground and other terminals

Always

10 kΩ or higher

OK

GO TO SMART KEY SYSTEM

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

15.

CHECK HARNESS AND CONNECTOR (N/ST RELAY - ECM - ENGINE STOP AND START ECU)

(a) Disconnect the ECM connector.

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

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

3 (N/ST relay) - A178-18 (STA)

Always

Below 1 Ω

3 (N/ST relay) and A178-18 (STA) - Body ground

Always

10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

16.

INSPECT N/ST RELAY

(a) Inspect the N/ST relay.

Click here 2023 - 2025 MY Corolla Corolla Hatchback [03/2023 -        ]; M20A-FKS (STARTING): RELAY: INSPECTION

NG

REPLACE ST NO. 2 RELAY

OK

17.

CHECK TERMINAL VOLTAGE (POWER SOURCE OF N/ST RELAY)

*1

No. 1 Engine Room Relay Block and Junction Block Assembly

*2

N/ST Relay

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

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

5 (N/ST relay) - Body ground

Engine started

11 to 14 V

NG

GO TO STEP 19

OK

18.

CHECK HARNESS AND CONNECTOR (ECM - N/ST RELAY)

(a) Disconnect the ECM connector.

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

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

C160-32 (NSR+) - 2 (N/ST relay)

Always

Below 1 Ω

C160-33 (NSR-) - 1 (N/ST relay)

Always

Below 1 Ω

C160-32 (NSR+) or 2 (N/ST relay) - Body ground and other terminals

Always

10 kΩ or higher

C160-33 (NSR-) or 1 (N/ST relay) - Body ground and other terminals

Always

10 kΩ or higher

OK

CHECK SHIFT LEVER POSITION SENSOR CIRCUIT

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

19.

CHECK HARNESS AND CONNECTOR (IGNITION SWITCH ASSEMBLY - N/ST RELAY)

(a) Disconnect the ignition switch assembly connector.

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

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

I12-5 (ST1) - 5 (N/ST relay)

Always

Below 1 Ω

I12-5 (ST1) or 5 (N/ST relay) - Body ground

Always

10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

20.

INSPECT IGNITION SWITCH ASSEMBLY

(a) Inspect the ignition switch assembly.

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

OK

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

NG

REPLACE IGNITION SWITCH ASSEMBLY

21.

READ VALUE USING TECHSTREAM (STARTER SW)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Data List / Starter SW.

Powertrain > Engine > Data List

Tester Display

Starter SW

(e) Check the value displayed on the Techstream when the ignition switch is turned to the ON and START positions.

OK:

Condition

Techstream Display (Starter SW)

Ignition switch ON

OFF

Engine started

ON

OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (ST RELAY - ECM)