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Home >> Lexus >> 2021 >> LS 500h AWD >> Repair and Diagnosis (Single Page) >> Body & Frame >> Door Locks >> Smart Access System (For Start) - Symptom Tests (2 Of 2) >> SMART ACCESS SYSTEM WITH PUSH-BUTTON START (for Start Function) >> Power Source Mode does not Change to ON (READY) [10/2017 - 10/2020] >> Procedure

Power Source Mode does not Change to ON (READY) [10/2017 - 10/2020]: Procedure

  1. CHECK POWER SWITCH CONDITION 
    1. Get into the vehicle while carrying an electrical key transmitter sub-assembly.
    2. Push the P position switch (shift position indication).
    3. With the brake pedal released, check that pressing the power switch causes the power source mode to change.

      Result

      Result Proceed to
      Power source mode changes: Off → on (ACC) → on (IG) → off A
      Power source mode does not change to on (ACC) or on (IG) B
      Power source mode changes to on (IG) but not to on (ACC) C
      Power source mode changes to on (ACC) but not to on (IG) D

    Result: 

    B 

    GO TO SMART ACCESS SYSTEM WITH PUSH-BUTTON START (for Start Function) (Power Source Mode does not Change to ON (IG and ACC)). Refer to  Power Source Mode does not Change to ON (IG and ACC) [10/2017 - 10/2023] 

    Result: 

    C 

    GO TO SMART ACCESS SYSTEM WITH PUSH-BUTTON START (for Start Function) (Power Source Mode does not Change to ON (IG)). Refer to  Power Source Mode does not Change to ON (IG) [10/2017 - 10/2020] 

    Result: 

    D 

    GO TO SMART ACCESS SYSTEM WITH PUSH-BUTTON START (for Start Function) (Power Source Mode does not Change to ON (IG)). Refer to  Power Source Mode does not Change to ON (IG) [10/2017 - 10/2020] 

    Result: 

    A 

    See step  2

  2. READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH1) 
    1. Connect the Techstream to the DLC3.
    2. Turn the power switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Body Electrical / Power Source Control / Data List.
    5. Read the Data List according to the display on the Techstream.

      Body Electrical > Power Source Control > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Stop Light Switch1 State of brake pedal OFF or ON OFF: Brake pedal released
      ON: Brake pedal depressed
      • Use this item to determine if the stop light switch assembly is malfunctioning.
      • The hybrid control system cannot be started when this item is OFF.
      • If the stop light switch assembly is malfunctioning, the hybrid control system can be started by pressing and holding the power switch for a certain period of time.

      Body Electrical > Power Source Control > Data List 

      Tester Display
      Stop Light Switch1

      OK

      The Techstream display changes correctly in response to the brake pedal operation.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  12

    Result: 

    OK 

    See step  3

  3. READ VALUE USING TECHSTREAM (SHIFT POSITION P) 
    1. Enter the following menus: Body Electrical / Power Source Control / Data List.
    2. Read the Data List according to the display on the Techstream.

      Body Electrical > Power Source Control > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Shift P Signal Pulse P position signal status Normal2, Normal3, Normal4, Normal5 or Unknown Normal2: Signal normal and park (P) selected
      Normal3: Signal normal and shift state other than (P)
      Normal4: Signal normal and park (N) selected
      Normal5: Signal normal and park other than (P) or (N) selected
      Unknown: -      		 Use this item to determine if the P position signal is malfunctioning.

      Body Electrical > Power Source Control > Data List 

      Tester Display
      Shift P Signal Pulse

      OK

      The Techstream display changes correctly in response to the shift state.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  9

    Result: 

    OK 

    See step  4

  4. READ VALUE USING TECHSTREAM (STARTER REQUEST SIGNAL) 
    1. Read the Data List according to the display on the Techstream.

      Body Electrical > Power Source Control > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Starter Request Signal Hybrid control system start request signal status OFF or ON OFF: The power switch is not pressed
      ON: With the shift state park (P) and the brake pedal depressed, the power switch is pressed and held
      • When the hybrid control system cannot be started due to a start request signal malfunction, OFF is displayed.
      • When the power switch is pressed, the duration of time that ON is displayed will be extremely short. As such, the power switch needs to be pressed and held for a certain period of time.

      Body Electrical > Power Source Control > Data List 

      Tester Display
      Starter Request Signal
      NOTE:

      Check that the key indicator display is displayed on the multi-information display in the combination meter assembly, and then press the power switch.

      OK

      The Techstream display changes correctly in response to the power switch operation.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  7

    Result: 

    OK 

    See step  5

  5. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - HYBRID VEHICLE CONTROL ECU ASSEMBLY) 
    1. Disconnect the G71 certification ECU (smart key ECU assembly) connector.
    2. Disconnect the G92 hybrid vehicle control ECU assembly connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G71-27 (ST2) - G92-9 (ST2) Always Below 1 Ω
      G71-27 (ST2) or G92-9 (ST2) - Other terminals and body ground Always 10 kΩ or higher
    4. Connect the G71 certification ECU (smart key ECU assembly) connector.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  6

  6. CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) 
    1. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      G71-27 (ST2) - Body ground With the brake pedal depressed, the power switch is pressed and held → After approximately 3 sec. has elapsed, the power switch is released 8.5 V or higher → 1 V or less
      GTY790750Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Certification ECU (Smart Key ECU Assembly))

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    GO TO HYBRID CONTROL SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING). Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2017 - 10/2023] 

    Result: 

    NG 

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [10/2017 - 09/2018]  , or refer to  REMOVAL [09/2018 - 10/2020] 

  7. CHECK STEERING LOCK 
    1. Check that the steering unlocks when the power switch is turned on (ACC).

      OK

      The steering unlocks.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    GO TO SMART ACCESS SYSTEM WITH PUSH-BUTTON START (for Start Function) (Unable to Unlock Steering Wheel (Hybrid Control System cannot Start)). Refer to  Unable to Unlock Steering Wheel (Hybrid Control System cannot Start) [10/2017 - 10/2022]  

    Result: 

    OK 

    See step  8

  8. CHECK SECURITY INDICATOR LIGHT (IMMOBILISER FUNCTION UNSET) 
    1. Get into the vehicle while carrying an electrical key transmitter sub-assembly.
    2. Push the P position switch (shift position indication).
    3. Press the power switch with the brake pedal released and check that the security indicator light changes from blinking to off at the same time that the power source mode changes to on (ACC).

      OK

      The security indicator light changes from blinking to off at the same time that the power source mode changes to on (ACC).

      HINT: 

      The immobiliser function can be determined to be operating correctly if the security indicator light changes from blinking to off at the same time that the power source mode changes to on (ACC).

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [10/2017 - 09/2018]  , or refer to  REMOVAL [09/2018 - 10/2020] 

    Result: 

    NG 

    GO TO SMART ACCESS SYSTEM WITH PUSH-BUTTON START (for Start Function) (Immobiliser System does not Operate Properly). Refer to  Immobiliser System does not Operate Properly [10/2017 - 10/2020]  

  9. CHECK SHIFT CONTROL ECU (OUTPUT TO CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)) 
    1. Using an oscilloscope, check the waveform.
      GTY800980Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Certification ECU (Smart Key ECU Assembly))      		 *b Waveform

      Measurement Condition

      Tester Connection Condition Tool Setting Specified Condition
      G71-22 (P) - G71-18 (E) Procedure:
      1. Power switch on (IG)
      2. Shift state park (P)
      		 10 V/DIV., 10 ms./DIV. Pulse generation
      (See waveform)

      HINT: 

      The waveform will vary depending on the shift state.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [10/2017 - 09/2018]  , or refer to  REMOVAL [09/2018 - 10/2020] 

    Result: 

    NG 

    See step  10

  10. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - SHIFT CONTROL ECU) 
    1. Disconnect the G71 certification ECU (smart key ECU assembly) connector.
    2. Disconnect the G81 shift control ECU connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G71-22 (P) - G81-13 (PPOS) Always Below 1 Ω
      G71-22 (P) or G81-13 (PPOS) - Other terminals and body ground 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 SHIFT CONTROL ECU 
    1. Connect the certification ECU (smart key ECU assembly) connector.
      GTY790752Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Certification ECU (Smart Key ECU Assembly))
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      G71-22 (P) - Body ground Procedure:
      1. Power switch on (IG)
      2. Shift state park (P)
      		 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE SHIFT CONTROL ECU. Refer to  REMOVAL [10/2017 - 09/2018]  , or refer to  REMOVAL [09/2018 - 10/2020] 

    Result: 

    NG 

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [10/2017 - 09/2018]  , or refer to  REMOVAL [09/2018 - 10/2020] 

  12. CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - POWER SUPPLY AND BODY GROUND) 
    1. Disconnect the A3 stop light switch assembly connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      A3-1 (B) - Body ground Power switch off 11 to 14 V
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A3-3 (GND) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  13

  13. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - STOP LIGHT SWITCH ASSEMBLY) 
    1. Disconnect the L31 certification ECU (smart key ECU assembly) connector.
    2. Disconnect the A77 hybrid vehicle control ECU assembly connector.
    3. Disconnect the A12 skid control ECU (brake actuator assembly) connector.
    4. Disconnect the G82 shift control ECU connector.
    5. Disconnect the cable from the negative (-) auxiliary battery terminal.
    6. Disconnect the L111 No. 3 semiconductor power integration ECU connector.
    7. Connect the cable to the negative (-) auxiliary battery terminal.

      Standard Resistance

      Tester Connection Condition Specified Condition
      L31-25 (STP1) - A3-2 (L) Always Below 1 Ω
      L31-25 (STP1) or A3-2 (L) - Other terminals and body ground Always 10 kΩ or higher
    8. Measure the resistance according to the value(s) in the table below.
    9. Connect the cable to the negative (-) auxiliary battery terminal.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  14

  14. INSPECT STOP LIGHT SWITCH ASSEMBLY 
    1. Inspect the stop light switch assembly.

      Refer to ON-VEHICLE INSPECTION [10/2017 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [10/2017 - 09/2018]  , or refer to  REMOVAL [09/2018 - 10/2020] 

    Result: 

    NG 

    REPLACE STOP LIGHT SWITCH ASSEMBLY. Refer to  REMOVAL [10/2017 - 09/2018]  , or refer to  REMOVAL [09/2018 - 10/2020] 

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