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Home >> Toyota >> 2022 >> Corolla Cross L, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 52 (Engine Control System (M20A-FKS) - Circuit Tests & Symptom Tests) >> SFI SYSTEM (for K121) >> Starter Signal Circuit [11/2023 - ] >> Procedure

Starter Signal Circuit [11/2023 - ]: Procedure

WARNING: This page is about a different car, the 2025 Toyota Corolla Cross and 2024 Toyota Corolla Cross. However, it is still accessible from the selected car via links, so may be relevant.
  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  18

    Result: 

    A 

    See step  2

  2. READ VALUE USING GTS (STARTER SW) 
    1. Enter the following menus.

      Powertrain > Engine > Data List 

      Tester Display
      Starter SW
    2. Check the value displayed on the GTS when the ignition switch is turned to the ON and START positions.

      OK

      Condition GTS Display (Starter SW)
      Ignition switch ON OFF
      Engine started ON

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  9

    Result: 

    OK 

    See step  3

  3. INSPECT ST RELAY 

    Refer to INSPECTION [09/2021 - ]

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPLACE ST RELAY 

    Result: 

    OK 

    See step  4

  4. INSPECT STARTER ASSEMBLY 

    Refer to INSPECTION [09/2021 - ]

    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 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) - C135-2 (ST) Always Below 1 Ω
      3 (ST relay) or C135-2 (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 HARNESS AND CONNECTOR (ST RELAY - ECM) 
    1. Remove the ST relay from the No. 1 engine room relay block.
    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) - A199-18 (STA) Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  7

  7. CHECK HARNESS AND CONNECTOR (ST RELAY - BODY GROUND) 
    1. Remove the ST relay from the No. 1 engine room relay block.
    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
      1 (ST relay holder) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  8

  8. CHECK TERMINAL VOLTAGE (POWER SOURCE OF ST RELAY) 
    1. Remove the ST relay from the No. 1 engine room relay block.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      5 (ST relay holder) - Body ground Always 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (AUXILIARY BATTERY - STARTER ASSEMBLY) 

    Result: 

    NG 

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

  9. CHECK STOP AND START SYSTEM 

    Refer to HOW TO PROCEED WITH TROUBLESHOOTING [09/2021 - ]

    Result

    Result
    OK
    NG

    Result: 

    NG 

    REPAIR STOP AND START SYSTEM 

    Result: 

    OK 

    See step  10

  10. CHECK VEHICLE TYPE 
    1. Check the vehicle specifications.

      Result

      Result Proceed to
      w/ Smart Key System A
      w/o Smart Key System B

    Result: 

    B 

    See step  13

    Result: 

    A 

    See step  11

  11. CHECK HARNESS AND CONNECTOR (ECM - CERTIFICATION ECU) 
    1. Disconnect the ECM connector.
    2. Disconnect the certification ECU (smart key ECU assembly) connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A199-81 (PPOS) - I223-3 (STA) Always Below 1 Ω
      A199-81 (PPOS) or I223-3 (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  12

  12. CHECK HARNESS AND CONNECTOR (ENGINE STOP AND START ECU - ECM - ST RELAY - CERTIFICATION ECU) 
    1. Disconnect the engine stop and start ECU connector.
    2. Disconnect the ECM connector.
    3. Remove the ST relay from the No. 1 engine room relay block.
    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
      A169-21 (STA) - A199-18 (STA) Always Below 1 Ω
      A169-21 (STA) - I223-10 (STAR) Always Below 1 Ω
      A169-21 (STA) - 2 (ST relay) Always Below 1 Ω
      A169-21 (STA), A199-18 (STA), I223-10 (STAR) or 2 (ST relay) - Body ground 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 

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

      Refer to INSPECTION [09/2021 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE N/ST RELAY 

    Result: 

    OK 

    See step  14

  14. INSPECT IGNITION OR STARTER SWITCH ASSEMBLY 
    1. Inspect the ignition or starter switch assembly.

      Refer to INSPECTION [09/2021 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE IGNITION OR STARTER SWITCH ASSEMBLY. Refer to  REMOVAL [09/2021 - ] 

    Result: 

    OK 

    See step  15

  15. CHECK HARNESS AND CONNECTOR (IGNITION OR STARTER SWITCH ASSEMBLY - N/ST RELAY) 
    1. Disconnect the ignition or starter switch assembly connector.
    2. Remove the N/ST relay from the No. 1 engine room relay block.
    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 holder) Always Below 1 Ω
      I12-5 (ST1) or 5 (N/ST relay holder) - 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  16

  16. 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.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      C144-32 (NSR+) - 2 (N/ST relay holder) Always Below 1 Ω
      C144-33 (NSR-) - 1 (N/ST relay holder) Always Below 1 Ω
      C144-32 (NSR+) or 2 (N/ST relay holder) - Body ground and other terminals Always 10 kΩ or higher
      C144-33 (NSR-) or 1 (N/ST relay holder) - 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  17

  17. CHECK HARNESS AND CONNECTOR (ENGINE STOP AND START ECU - ECM - ST RELAY - N/ST RELAY) 
    1. Disconnect the engine stop and start ECU connector.
    2. Disconnect the ECM connector.
    3. Remove the ST relay from the No. 1 engine room relay block.
    4. Remove the N/ST relay from the No. 1 engine room relay block.
    5. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A169-21 (STA) - A199-18 (STA) Always Below 1 Ω
      A169-21 (STA) - 3 (N/ST relay) Always Below 1 Ω
      A169-21 (STA) - 2 (ST relay) Always Below 1 Ω
      A169-21 (STA), A199-18 (STA), 3 (N/ST relay) or 2 (ST relay) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

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

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  18. READ VALUE USING GTS (STARTER SW) 
    1. Enter the following menus.

      Powertrain > Engine > Data List 

      Tester Display
      Starter SW
    2. Check the value displayed on the GTS when the ignition switch is turned to the ON and START positions.

      OK

      Condition GTS 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 [11/2023 - ] 

    Result: 

    NG 

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

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