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Home >> Toyota >> 2020 >> Corolla L >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 29 (Engine Control System (M20A-FKS) - Circuit Tests (5 Of 6)) >> SFI System >> Starter Signal Circuit [03/2023 - 09/2024] >> Procedure

Starter Signal Circuit [03/2023 - 09/2024]: Procedure

WARNING: This page is about a different variant/trim than selected.
  1. CHECK WHETHER ENGINE CAN BE CRANKED 
    1. Check if the engine can be cranked.

      Result

      Result Proceed to
      Engine cannot be cranked A
      Engine can be cranked B

    Result: 

    B 

    See step  21

    Result: 

    A 

    See step  2

  2. READ VALUE USING TECHSTREAM (STARTER SW) 
    1. Connect the Techstream to the DLC3.
    2. Turn the ignition switch to ON.
    3. Turn the Techstream on.
    4. Enter the following menus: Powertrain / Engine / Data List / Starter SW.

      Powertrain > Engine > Data List 

      Tester Display
      Starter SW
    5. 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

      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

    Result: 

    B 

    See step  11

    Result: 

    C 

    See step  14

    Result: 

    D 

    See step  15

    Result: 

    A 

    See step  3

  3. INSPECT ST RELAY 
    1. Inspect the ST relay.

      Refer to INSPECTION [03/2023 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE ST RELAY 

    Result: 

    OK 

    See step  4

  4. INSPECT STARTER ASSEMBLY 
    1. Inspect the starter assembly.

      Refer to INSPECTION [06/2018 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE STARTER ASSEMBLY 

    Refer to REMOVAL [11/2022 - ]

    Result: 

    OK 

    See step  5

  5. CHECK HARNESS AND CONNECTOR (ST RELAY - STARTER ASSEMBLY) 
    1. Remove the ST relay from the No. 1 engine room relay block and No. 1 junction block assembly.
    2. Disconnect the starter assembly connector.
    3. 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

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  6

  6. CHECK TERMINAL VOLTAGE (BATTERY - STARTER ASSEMBLY) 
    1. Disconnect the cable from the negative (-) battery terminal.
    2. Disconnect the cable from the positive (+) battery terminal.
    3. Disconnect the starter assembly connector.
    4. 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

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  7

  7. CHECK TERMINAL VOLTAGE (POWER SOURCE OF ST RELAY) 
    GTY1107513Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *1 No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly
    *2 ST Relay
    1. Remove the ST relay from the No. 1 engine room relay block and No. 1 junction block assembly.
    2. 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

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

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

    Result: 

    OK 

    See step  8

  8. CHECK HARNESS AND CONNECTOR (ST RELAY - BODY GROUND) 
    1. Remove the ST relay from the No. 1 engine room relay block and No. 1 junction block assembly.
    2. 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

      Result Proceed to
      OK (for K120) A
      OK (for K121) B
      NG C

    Result: 

    B 

    See step  10

    Result: 

    C 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    A 

    See step  9

  9. CHECK HARNESS AND CONNECTOR (ST RELAY - PARK/NEUTRAL POSITION SWITCH ASSEMBLY) 
    1. Remove the ST relay from the No. 1 engine room relay block and No. 1 junction block assembly.
    2. Disconnect the park/neutral position switch assembly connector.
    3. 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

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE 

    Refer to PROBLEM SYMPTOMS TABLE [03/2023 - 09/2024]

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  10. CHECK HARNESS AND CONNECTOR (ST RELAY - ECM) 
    1. Remove the ST relay from the No. 1 engine room relay block and No. 1 junction block assembly.
    2. Disconnect the ECM connector.
    3. 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

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE 

    Refer to PROBLEM SYMPTOMS TABLE [03/2023 - 09/2024]

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  11. INSPECT PARK/NEUTRAL POSITION SWITCH ASSEMBLY 
    1. Inspect the park/neutral position switch assembly.

      Refer to INSPECTION [06/2018 - 09/2024]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE PARK/NEUTRAL POSITION SWITCH ASSEMBLY 

    Refer to REMOVAL [11/2022 - 09/2024]

    Result: 

    OK 

    See step  12

  12. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - PARK/NEUTRAL POSITION SWITCH ASSEMBLY - ECM) 
    1. Disconnect the certification ECU (smart key ECU assembly) connector.
    2. Disconnect the park/neutral position switch assembly connector.
    3. Disconnect the ECM connector.
    4. 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

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  13

  13. CHECK HARNESS AND CONNECTOR (STA SIGNAL CIRCUIT) 
    1. Disconnect the park/neutral position switch assembly connector.
    2. Remove the ST relay from the No. 1 engine room relay block and No. 1 junction block assembly.
    3. Disconnect the ECM connector.
    4. Disconnect the certification ECU (smart key ECU assembly) connector.
    5. 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

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    GO TO SMART KEY SYSTEM 

    Refer to HOW TO PROCEED WITH TROUBLESHOOTING [11/2022 - ]

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  14. CHECK HARNESS AND CONNECTOR (STA SIGNAL CIRCUIT) 
    1. Remove the ST relay from the No. 1 engine room relay block and No. 1 junction block assembly.
    2. Disconnect the ECM connector.
    3. Disconnect the certification ECU (smart key ECU assembly) connector.
    4. 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

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    GO TO SMART KEY SYSTEM 

    Refer to HOW TO PROCEED WITH TROUBLESHOOTING [11/2022 - ]

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  15. CHECK HARNESS AND CONNECTOR (N/ST RELAY - ECM - ENGINE STOP AND START ECU) 
    1. Disconnect the ECM connector.
    2. Remove the N/ST relay from the No. 1 engine room relay block and junction block assembly.
    3. 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

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  16

  16. INSPECT N/ST RELAY 
    1. Inspect the N/ST relay.

      Refer to INSPECTION [03/2023 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE ST NO. 2 RELAY 

    Result: 

    OK 

    See step  17

  17. CHECK TERMINAL VOLTAGE (POWER SOURCE OF N/ST RELAY) 
    GTY1181124Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *1 No. 1 Engine Room Relay Block and Junction Block Assembly
    *2 N/ST Relay
    1. Remove the N/ST relay from the No. 1 engine room relay block and junction block assembly.
    2. 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

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  19

    Result: 

    OK 

    See step  18

  18. CHECK HARNESS AND CONNECTOR (ECM - N/ST RELAY) 
    1. Disconnect the ECM connector.
    2. Remove the N/ST relay from the No. 1 engine room relay block and junction block assembly.
    3. 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

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    CHECK SHIFT LEVER POSITION SENSOR CIRCUIT 

    Refer to DTC P0705-62: Transmission Range Sensor "A" Signal Compare Failure [03/2023 - ]

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  19. CHECK HARNESS AND CONNECTOR (IGNITION SWITCH ASSEMBLY - N/ST RELAY) 
    1. Disconnect the ignition switch assembly connector.
    2. Remove the N/ST relay from the No. 1 engine room relay block and junction block assembly.
    3. 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

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  20

  20. INSPECT IGNITION SWITCH ASSEMBLY 
    1. Inspect the ignition switch assembly.

      Refer to INSPECTION [01/2019 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

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

    Result: 

    NG 

    REPLACE IGNITION SWITCH ASSEMBLY 

    Refer to REMOVAL [01/2019 - ]

  21. READ VALUE USING TECHSTREAM (STARTER SW) 
    1. Connect the Techstream to the DLC3.
    2. Turn the ignition switch to ON.
    3. Turn the Techstream on.
    4. Enter the following menus: Powertrain / Engine / Data List / Starter SW.

      Powertrain > Engine > Data List 

      Tester Display
      Starter SW
    5. 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
      NG

    Result: 

    OK 

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE 

    Refer to PROBLEM SYMPTOMS TABLE [03/2023 - 09/2024]

    Result: 

    NG 

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

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