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Home >> Lexus >> 2019 >> ES 350 Luxury >> Repair and Diagnosis >> External Pages >> Different car >> Section 93 (Engine Control System (A25A-FKS) - Diagnostic Codes (12 Of 12), Circuit Tests & Symptom Tests (1 Of 2)) >> SFI System >> Starter Signal Circuit [08/2020 - ] >> Procedure

Starter Signal Circuit [08/2020 - ]: Procedure

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  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  12

    Result: 

    A 

    See step  2

  2. READ VALUE USING TECHSTREAM (STARTER SW) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    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 engine switch is turned on (IG) and the engine is cranked.

      OK

      Condition Techstream Display (Starter SW)
      Engine switch on (IG) OFF
      Cranking position ON

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  9

    Result: 

    OK 

    See step  3

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

      Refer to INSPECTION [08/2020 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE RELAY (ST RELAY) 

    Result: 

    OK 

    See step  4

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

      Refer to INSPECTION [08/2020 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE STARTER ASSEMBLY. Refer to  REMOVAL [08/2020 - 08/2021]  , or refer to  REMOVAL [08/2021 - 09/2022]  , or refer to  REMOVAL [09/2022 - ] 

    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) - C79-1 Always Below 1 Ω
      3 (ST relay) or C79-1 - 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 - 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
      1 (ST relay) - Body ground 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 (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 - D1-1 Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  8

  8. CHECK HARNESS AND CONNECTOR (PARK/NEUTRAL POSITION SWITCH ASSEMBLY - SMART KEY ECU ASSEMBLY - ST RELAY) 
    1. Remove the ST relay from the No. 1 engine room relay block and No. 1 junction block assembly.
    2. Disconnect the certification ECU (smart key ECU assembly) connector.
    3. Disconnect the park/neutral position switch assembly connector.
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      C31-9 (L) - 2 (ST relay) Always Below 1 Ω
      A15-20 (STA) - 2 (ST relay) Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

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

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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

      Refer to INSPECTION [08/2020 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE PARK/NEUTRAL POSITION SWITCH ASSEMBLY. Refer to  REMOVAL [08/2020 - 08/2021]  , or refer to  REMOVAL [08/2021 - 09/2022]  , or refer to  REMOVAL [09/2022 - ] 

    Result: 

    OK 

    See step  10

  10. CHECK HARNESS AND CONNECTOR (PARK/NEUTRAL POSITION SWITCH ASSEMBLY - ECM - ST RELAY - CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)) 
    1. Disconnect the park/neutral position switch assembly connector.
    2. Disconnect the ECM connector.
    3. Remove the ST relay from the No. 1 engine room relay block and No. 1 junction block assembly.
    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
      C31-9 (L) - A28-30 (STA) Always Below 1 Ω
      C31-9 (L), A28-30 (STA), 2 (ST relay) or A15-20 (STA) - 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  11

  11. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - PARK/NEUTRAL POSITION SWITCH ASSEMBLY - ECM) 
    1. Disconnect the park/neutral position switch assembly connector.
    2. Disconnect the certification ECU (smart key ECU 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
      A15-9 (STAR) - C31-4 (B) Always Below 1 Ω
      A15-9 (STAR) - A28-23 (NSW) Always Below 1 Ω
      A15-9 (STAR), C31-4 (B) or A28-23 (NSW) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    GO TO SMART ACCESS SYSTEM WITH PUSH-BUTTON START. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [06/2018 - 09/2022]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2022 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  12. READ VALUE USING TECHSTREAM (STARTER SW) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    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 engine switch is turned on (IG) and the engine is cranked.

      OK

      Condition Techstream Display (Starter SW)
      Engine switch on (IG) OFF
      Cranking position ON

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [08/2020 - ] 

    Result: 

    NG 

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

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