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Home >> Lexus >> 2009 >> IS 250 RWD, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (DTCS P0420 - U0101 & Circuit Tests) >> SFI System >> Cranking Holding Function Circuit >> Procedure
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Cranking Holding Function Circuit: Procedure

  1. CHECK CRANKING 
    1. When starting the engine, check whether the starter motor starts.

    OK → CHECK FOR INTERMITTENT PROBLEMS 

    NG: Go to next step 

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

      Standard

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

    OK → See step   6 

    NG: Go to next step 

  3. INSPECT ECM (STAR AND STSW VOLTAGE) 
    1. Measure the voltage according to the value(s) in the table below while cranking the engine.
      Fig 1: Identifying ECM Connectors
      GTY131166Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard voltage

      Tester Connection Specified Condition
      STAR (E4-4) - E1 (E4-7) 9 to 14 V
      STSW (A5-19) - E1 (E4-7) 9 to 14 V

      Result

      Terminal STAR Terminal STSW Proceed to
      9 to 14 V 9 to 14 V A
      0 V 9 to 14 V B
      0 V 0 V C

    C → See step   10 

    B → REPLACE ECM 

    A: Go to next step 

  4. INSPECT ST CUT RELAY 
    1. Remove the ST CUT relay from the engine room R/B No. 2.
      Fig 2: 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 Specified Condition
      3 - 5 10 kΩ or higher
      3 - 5 Below 1 Ω
      (when battery voltage applied to terminals 1 and 2)

    NG → REPLACE ST CUT RELAY 

    OK: Go to next step 

  5. INSPECT PARK/NEUTRAL POSITION SWITCH ASSEMBLY (A/T) OR CLUTCH PEDAL SWITCH ASSEMBLY (M/T) 
    1. Disconnect the park/neutral position (PNP) switch (A/T) or clutch pedal switch (M/T) connector.
      Fig 3: Identifying Connector Terminals
      GTY145797Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance (A/T)

      Shift Position Tester Connection Specified Condition
      P 4 - 5 Below 1 Ω
      N 4 - 5 Below 1 Ω

      Standard resistance (M/T)

      Clutch Pedal Operation Tester Connection Specified Condition
      Depressed 1 - 2 Below 1 Ω

    NG → REPLACE PARK/NEUTRAL POSITION SWITCH (A/T) OR CLUTCH PEDAL SWITCH (M/T) 

    OK → CHECK AND REPAIR HARNESS AND CONNECTOR ((PARK/NEUTRAL POSITION SWITCH - ECM, ECM - ST CUT RELAY, ST) 

  6. INSPECT STARTER RELAY 
    1. Remove the STARTER relay from the engine room R/B No. 1.
      Fig 4: Inspecting Starter Relay
      GTY102844Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance

      Tester Connection Specified Condition
      3 - 5 10 kΩ or higher
      3 - 5 Below 1 Ω
      (when battery voltage applied to terminals 1 and 2)

    NG → REPLACE STARTER RELAY 

    OK: Go to next step 

  7. CHECK HARNESS AND CONNECTOR (PNP SWITCH (A/T) OR CLUTCH PEDAL SWITCH (M/T) - ST RELAY) 
    1. Check the harness and the connectors between the park/neutral position switch and the starter relay.
      Fig 5: Identifying Terminals Of Relay & Connectors
      GTY145798Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      1. Disconnect the E45*1, A24*2 switch connector.

        *1: A/T

        *2: M/T

      2. Remove the starter relay from the engine room R/B No. 1.
      3. Measure the resistance according to the value(s) in the table below.

        Standard resistance (A/T) (Check for open)

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

        Standard resistance (M/T) (Check for open)

        Tester Connection Specified Condition
        Clutch pedal switch (A24-2) - STARTER relay (1) Below 1 Ω

        Standard resistance (A/T) (Check for short)

        Tester Connection Specified Condition
        Park/Neutral position switch (E45-5) or STARTER relay (1) - Body ground 10 kΩ or higher

        Standard resistance (M/T) (Check for short)

        Tester Connection Specified Condition
        Clutch pedal switch (A24-2) or STARTER relay (1) - Body ground 10 kΩ or higher
    2. Check the harness and the connector between the starter relay and the body ground.
      1. Remove the starter relay from the engine room R/B No. 1.
      2. Measure the resistance according to the value(s) in the table below.

        Standard resistance (Check for open)

        Tester Connection Specified Condition
        STARTER relay (2) - Body ground Below 1 Ω

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  8. INSPECT ENGINE ROOM RELAY BLOCK (STARTER RELAY VOLTAGE) 
    1. Remove the starter relay from the engine room R/B No. 1.
      Fig 6: Identifying Starter Relay
      GTY141798Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the voltage according to the value(s) in the table below.

      Standard voltage

      Tester Connection Specified Condition
      STARTER relay (5) - Body ground 9 to 14 V

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  9. INSPECT STARTER ASSEMBLY 

    NG → REPAIR OR REPLACE STARTER ASSEMBLY 

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

  10. 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 7: Identifying Connector Terminals
      GTY128972Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      1. Disconnect the power source control ECU connector.
      2. Disconnect the A5 ECM connector.
      3. Measure the resistance according to the value(s) in the table below.

        Standard resistance (Check for open)

        Tester Connection Specified Condition
        J55-39 (STSW) - A5-19 (STSW) Below 1 Ω

        Standard resistance (Check for short)

        Tester Connection Specified Condition
        J55-39 (STSW) or A5-19 (STSW) - Body ground 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → GO TO SMART ACCESS SYSTEM WITH PUSH-BUTTON START 

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