LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 2009 >> IS F >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control (SFI) System (Diagnostic Codes & Circuit Tests) >> SFI System >> Cranking Holding Function Circuit >> Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Cranking Holding Function Circuit: Procedure

  1. READ VALUE USING TECHSTREAM (STA SIGNAL) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG) and turn the Techstream ON.
    3. Enter the following menus: Powertrain / Engine / Data List / Starter Signal.
    4. Check the result when the engine switch is turned on (IG) and the engine is started.

      Standard

      Starter Signal Engine Switch Position
      OFF on (IG)
      ON ENGINE START

    NG → See step   9 

    OK: Go to next step 

  2. INSPECT STARTER RELAY 
    1. Remove the STARTER relay from the engine room No. 1 relay block.
      Fig 1: Inspecting Starter Relay
      GTY120773Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      3 - 5 When no battery voltage applied to terminals 1 and 2 10 kΩ or higher
      3 - 5 When battery voltage applied to terminals 1 and 2 Below 1 Ω
    3. Reinstall the STARTER relay.

    NG → REPLACE STARTER RELAY 

    OK: Go to next step 

  3. INSPECT FUSIBLE LINK BLOCK ASSEMBLY (STARTER FUSE) 
    1. Remove the fusible link block assembly from the engine room No. 1 relay block.
      Fig 2: Identifying Fusible Link Block Assembly
      GTY120979Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      1B-1 - 1G-4 Always Below 1 Ω
    3. Reinstall the fusible link block assembly.

    NG → REPLACE FUSIBLE LINK BLOCK ASSEMBLY (STARTER FUSE) 

    OK: Go to next step 

  4. CHECK HARNESS AND CONNECTOR (PARK/NEUTRAL POSITION SWITCH - STARTER RELAY) 
    1. Disconnect the park/neutral position switch connector.
      Fig 3: Identifying Park/Neutral Position Switch Connector E45 & Starter Relay
      GTY148946Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Remove the STARTER relay from the engine room No. 1 relay block.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for Open)

      Tester Connection Condition Specified Condition
      Park/Neutral position switch (E45-5) - STARTER relay (1) Always Below 1 Ω

      Standard Resistance (Check for Short)

      Tester Connection Condition Specified Condition
      Park/Neutral position switch (E45-5) or STARTER relay (1) - Body ground Always 10 kΩ or higher
    4. Reconnect the park/neutral position switch connector.
    5. Reinstall the STARTER relay.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  5. CHECK HARNESS AND CONNECTOR (STARTER RELAY - BODY GROUND) 
    1. Remove the STARTER relay from the engine room No. 1 relay block.
      Fig 4: Identifying Starter Relay
      GTY105670Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      STARTER relay (2) - Body ground Always Below 1 Ω
    3. Reinstall the STARTER relay.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (STARTER RELAY - BODY GROUND) 

    OK: Go to next step 

  6. INSPECT ENGINE ROOM RELAY BLOCK (STARTER RELAY VOLTAGE) 
    1. Remove the STARTER relay from the engine room No. 1 relay block.
      Fig 5: Identifying Starter Relay
      GTY105670Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      STARTER relay (5) - Body ground Always 11 to 14 V
    3. Reinstall the STARTER relay.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (STARTER RELAY - BATTERY) 

    OK: Go to next step 

  7. INSPECT STARTER ASSEMBLY 
    1. Inspect the starter assembly. Refer to INSPECTION .

    NG → REPAIR OR REPLACE STARTER ASSEMBLY 

    OK: Go to next step 

  8. CHECK HARNESS AND CONNECTOR (STARTER RELAY - STARTER ASSEMBLY) 
    1. Remove the STARTER relay from the engine room No. 1 relay block.
      Fig 6: Identifying Starter Relay & Starter Connector E10
      GTY148947Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the starter connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      STARTER relay (3) - E10-1 Always Below 1 Ω
    4. Reinstall the STARTER relay.
    5. Reconnect the starter connector.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (STARTER RELAY - STARTER ASSEMBLY) 

    OK → REPAIR OR REPLACE HARNESS OR CONNECTOR (STARTER - BATTERY) 

  9. INSPECT ECM (STAR AND STSW VOLTAGE) 
    1. Measure the voltage according to the value(s) in the table below while cranking the engine.
      Fig 7: Identifying ECM Connector E6 And A5
      GTY146231Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Voltage

      Tester Connection Condition Specified Condition
      A5-2 (STAR) - E6-1(E1) Cranking 11 to 14 V
      A5-27 (STSW) - E6-1 (E1) Cranking 11 to 14 V

      Result

      Terminal STAR Terminal STSW Proceed to
      11 to 14 V 11 to 14 V A
      0 V 11 to 14 V B
      0 V 0 V C

    C → See step   17 

    B → See step   18 

    A: Go to next step 

  10. INSPECT ST CUT RELAY 
    1. Remove the ST CUT relay from the engine room No. 2 relay block.
      Fig 8: Inspecting ST CUT Relay
      GTY100961Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      3 - 5 When no battery voltage applied to terminals 1 and 2 10 kΩ or higher
      3 - 5 When battery voltage applied to terminals 1 and 2 Below 1 Ω
    3. Reinstall the ST CUT relay.

    NG → REPLACE ST CUT RELAY 

    OK: Go to next step 

  11. INSPECT PARK/NEUTRAL POSITION SWITCH ASSEMBLY 
    1. Disconnect the park/neutral position switch connector.
      Fig 9: Identifying Park/Neutral Position Switch Connector
      GTY122197Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Shift Position Specified Condition
      4 - 5 P Below 1 Ω
      4 - 5 N Below 1 Ω
    3. Reconnect the park/neutral position switch connector.

    NG → See step   19 

    OK: Go to next step 

  12. CHECK HARNESS AND CONNECTOR (ST CUT RELAY POWER SOURCE) 
    1. Remove the ST CUT relay from the engine room No. 2 relay block.
      Fig 10: Identifying ST Cut Relay
      GTY143762Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Turn the engine switch on (IG).
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      ST CUT relay (1) - Body ground Engine switch on (IG) 11 to 14 V
    4. Reinstall the ST CUT relay.

    NG → See step   16 

    OK: Go to next step 

  13. CHECK HARNESS AND CONNECTOR (ST CUT RELAY - BODY GROUND) 
    1. Remove the ST CUT relay from the engine room No. 2 relay block.
      Fig 11: Identifying ST Cut Relay
      GTY143762Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      ST CUT relay (2) - Body ground Always Below 1 Ω
    3. Reinstall the ST CUT relay.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  14. CHECK HARNESS AND CONNECTOR (ECM - ST CUT RELAY) 
    1. Disconnect the ECM connector.
      Fig 12: Identifying ST Cut Relay & ECM Connector A5
      GTY120896Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Remove the ST CUT relay from the engine room No. 2 relay block.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A5-2 (STAR) - ST CUT relay (3) Always Below 1 Ω
    4. Reinstall the ST CUT relay.
    5. Reconnect the ECM connector.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  15. CHECK HARNESS AND CONNECTOR (PARK/NEUTRAL POSITION SWITCH - ST CUT RELAY) 
    1. Disconnect the park/neutral position switch connector.
      Fig 13: Identifying Park/Neutral Position Switch Connector E45 And ST Cut Relay Terminal
      GTY120897Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Remove the ST CUT relay from the engine room No. 2 relay block.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for Open)

      Tester Connection Condition Specified Condition
      Park/Neutral position switch (E45-4) - ST CUT relay (5) Always Below 1 Ω

      Standard Resistance (Check for Short)

      Tester Connection Condition Specified Condition
      Park/Neutral position switch (E45-4) or ST CUT relay (5) - Body ground Always 10 kΩ or higher
    4. Reconnect the park/neutral position switch connector.
    5. Reinstall the ST CUT relay.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (ST CUT RELAY - PARK/NEUTRAL POSITION SWITCH) 

    OK → REPAIR OR REPLACE HARNESS OR CONNECTOR (PARK/NEUTRAL POSITION SWITCH - ECM) 

  16. CHECK HARNESS AND CONNECTOR (ST CUT RELAY - POWER SOURCE CONTROL ECU) 
    1. Remove the ST CUT relay from the engine room No. 2 relay block.
      Fig 14: Identifying Power Source Control ECU Connector J55 & ST Cut Relay
      GTY137364Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the power source control ECU connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      ST CUT relay (2) - J55-35 (IG2D) Always Below 1 Ω
    4. Reinstall the ST CUT relay.
    5. Reconnect the power source control ECU connector.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → See step   20 

  17. CHECK HARNESS AND CONNECTOR (POWER SOURCE CONTROL ECU - ECM) 
    1. Check the harness and the connectors between the power source control ECU and ECM.
      Fig 15: Identifying Power Source Control ECu Connector J55 & ECM Connector A5
      GTY140624Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      1. Disconnect the power source control ECU connector.
      2. Disconnect the ECM connector.
      3. Measure the resistance according to the value(s) in the table below.

        Standard Resistance (Check for Open)

        Tester Connection Condition Specified Condition
        J55-39 (STSW) - A5-27 (STSW) Always Below 1 Ω

        Standard Resistance (Check for Short)

        Tester Connection Condition Specified Condition
        J55-39 (STSW) or A5-27 (STSW) - Body ground Always 10 kΩ or higher
      4. Reconnect the ECM connector and power source control ECU connector.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → See step   21 

  18. REPLACE ECM. Refer to  REMOVAL 
  19. REPLACE PARK/NEUTRAL POSITION SWITCH ASSEMBLY. Refer to  REMOVAL 
  20. GO TO SMART ACCESS SYSTEM WITH PUSH-BUTTON START. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING 
  21. GO TO SMART ACCESS SYSTEM WITH PUSH-BUTTON START. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING 
scientia non olet · About LEMON Manuals