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Home >> Lexus >> 2019 >> LS 500 Base, AWD >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Anti-Theft Systems >> Smart Access System (For Start) - Diagnostic Codes (2 Of 2) & Symptom Tests (1 Of 2) >> SMART ACCESS SYSTEM WITH PUSH-BUTTON START (for Start Function) >> Engine does not Start [12/2017 - 10/2020] >> Procedure

Engine does not Start [12/2017 - 10/2020]: Procedure

  1. CHECK ENGINE 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 engine 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 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) [12/2017 - 10/2023]  

    Result: 

    C 

    GO TO SMART ACCESS SYSTEM WITH PUSH-BUTTON START (for Start Function) (Power Source Mode does not Change to ON (ACC)). Refer to  Power Source Mode does not Change to ON (ACC) [12/2017 - 10/2023] 

    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) [12/2017 - 10/2023] 

    Result: 

    A 

    See step  2

  2. READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH1) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine 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 engine cannot be started when this item is OFF.
      • If the stop light switch assembly is malfunctioning, the engine can be started by pressing and holding the engine 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  19

    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  16

    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 Engine start request signal status OFF or ON OFF: The engine switch is not pressed
      ON: With the shift state park (P) and the brake pedal depressed, the engine switch is pressed and held
      • When the engine cannot be started due to a start request signal malfunction, OFF is displayed.
      • When the engine switch is pressed, the duration of time that ON is displayed will be extremely short. As such, the engine 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 engine switch.

      OK

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

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  14

    Result: 

    OK 

    See step  5

  5. READ VALUE USING TECHSTREAM (STARTER SW) 
    1. Get into the vehicle while carrying an electrical key transmitter sub-assembly.
    2. Shift state park (P).
    3. Enter the following menus: Body Electrical / Starting Control / Data List.
    4. Read the Data List while pressing the engine switch with the brake pedal depressed according to the display on the Techstream.

      Body Electrical > Starting Control > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Starter SW Starter operation request OFF or ON OFF: Starter operation not requested
      ON: Starter operation requested      		 When OFF is displayed, the engine will not crank.

      Body Electrical > Starting Control > Data List 

      Tester Display
      Starter SW

      OK

      The Techstream display changes.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [12/2017 - 09/2018]  , or refer to  REMOVAL [09/2018 - 10/2020] 

    Result: 

    OK 

    See step  6

  6. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - ST NO. 1 RELAY) 
    1. Remove the ST NO. 1 relay.
      GTY801850Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a No. 1 Engine Room Relay Block
      (ST No. 1 Relay Installation Terminal)
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      ST NO. 1 relay installation terminal 2 - Body ground Engine switch pressed and held with brake pedal depressed (starter on) → Approximately 1 second after engine switch released (starter off) 6 V or higher* → 1.0 V or less

      HINT: 

      *: While the engine is cranking, the battery voltage may drop to approximately 6 V.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  11

    Result: 

    OK 

    See step  7

  7. CHECK HARNESS AND CONNECTOR (ST NO. 1 RELAY - POWER SUPPLY AND BODY GROUND) 
    1. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      ST NO. 1 relay installation terminal 1 - Body ground Always Below 1 Ω
      GTY801850Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a No. 1 Engine Room Relay Block
      (ST No. 1 Relay Installation Terminal)
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      ST NO. 1 relay installation terminal 5 - Body ground Always 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  8

  8. INSPECT ST NO. 1 RELAY 
    1. Inspect the ST NO. 1 relay.

      Refer to ON-VEHICLE INSPECTION [12/2017 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE ST NO. 1 RELAY 

    Result: 

    OK 

    See step  9

  9. CHECK HARNESS AND CONNECTOR (ST NO. 1 RELAY - STARTER ASSEMBLY) 
    1. Disconnect the D58*1 or D59*2 starter assembly connector.
      1. *1: for 2WD
      2. *2: for AWD
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      ST NO. 1 relay installation terminal 3 - D58-1 (ST)*1 Always Below 1 Ω
      ST NO. 1 relay installation terminal 3 - D59-1 (ST)*2 Always Always
      ST NO. 1 relay installation terminal 3 or D58-1 (ST) - Other terminals and body ground*1 Always 10 kΩ or higher
      ST NO. 1 relay installation terminal 3 or D59-1 (ST) - Other terminals and body ground*2 Always 10 kΩ or higher
      1. *1: for 2WD
      2. *2: for AWD

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  10

  10. CHECK HARNESS AND CONNECTOR (STARTER ASSEMBLY - POWER SUPPLY) 
    1. Disconnect the starter assembly connector.
      GTY777195Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Wire harness connector
      (to Starter Assembly)
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      D60-1 (B) - Body ground Always 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE STARTER ASSEMBLY. Refer to  REMOVAL [12/2017 - 09/2018]  , or refer to  REMOVAL [09/2018 - 10/2020] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  11. CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) (TERMINAL STAR) 
    1. Install the ST relay NO. 1
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A22-9 (STAR) - Body ground Engine switch pressed and held with brake pedal depressed (starter on) → Approximately 1 second after engine switch released (starter off) 6 V or higher* → 1.0 V or less
      GTY807585Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Certification ECU (Smart Key ECU Assembly))

      HINT: 

      *: While the engine is cranking, the battery voltage may drop to approximately 6 V.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    NG 

    See step  12

  12. CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) (TERMINAL STAR) 
    1. Disconnect the A95 ECM connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A22-9 (STAR) - Body ground Engine switch pressed and held with brake pedal depressed (starter on) → Approximately 1 second after engine switch released (starter off) 6 V or higher* → 1.0 V or less
      GTY807585Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Certification ECU (Smart Key ECU Assembly))

      HINT: 

      *: While the engine is cranking, the battery voltage may drop to approximately 6 V.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE ECM. Refer to  REMOVAL [12/2017 - 09/2018]  , or refer to  REMOVAL [09/2018 - 10/2020] 

    Result: 

    NG 

    See step  13

  13. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - ECM) 
    1. Disconnect the A22 certification ECU (smart key ECU assembly) connector.
    2. Remove the ST NO. 1 relay.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A22-9 (STAR) - A22-20 (STA) Always Below 1 Ω
      A22-9 (STAR) - A95-16 (STA) Always Below 1 Ω
      A22-9 (STAR) - ST NO. 1 relay installation terminal 2 Always Below 1 Ω
      A22-9 (STAR) - Other terminals and body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [12/2017 - 09/2018]  , or refer to  REMOVAL [09/2018 - 10/2020] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  14. CHECK STEERING LOCK 
    1. Check that the steering unlocks when the engine 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 (Engine cannot Start)). Refer to  Unable to Unlock Steering Wheel (Engine cannot Start) [12/2017 - 10/2022] 

    Result: 

    OK 

    See step  15

  15. 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 engine 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 [12/2017 - 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 [12/2017 - 10/2023] 

  16. CHECK SHIFT CONTROL ECU (OUTPUT TO CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)) 
    1. Using an oscilloscope, check the waveform.
      GTY825820Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Certification ECU (Smart Key ECUAssembly))      		 *b Waveform

      Measurement Condition

      Tester Connection Condition Tool Setting Specified Condition
      G71-22 (P) - G71-18 (E) Procedure:
      1. Engine 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 [12/2017 - 09/2018]  , or refer to  REMOVAL [09/2018 - 10/2020] 

    Result: 

    NG 

    See step  17

  17. 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  18

  18. CHECK SHIFT CONTROL ECU 
    1. Reconnect the G71 certification ECU (smart key ECU assembly) connector.
      GTY790746Courtesy 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) - Other terminals and body ground Procedure:
      1. Engine switch on (IG)
      2. Shift state park (P)
      		 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE SHIFT CONTROL ECU 

    for: AGA0E

    Refer to REMOVAL [12/2017 - 09/2018] , or refer to REMOVAL [09/2018 - 10/2020]

    for: AGA0F

    Refer to REMOVAL [12/2017 - 09/2018] , or refer to REMOVAL [09/2018 - 10/2020]

    Result: 

    NG 

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [12/2017 - 09/2018]  , or refer to  REMOVAL [09/2018 - 10/2020] 

  19. 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 Condition Specified Condition
      A3-1 (B) - Body ground Always 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  20

  20. 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 A95 ECM connector.
    3. Disconnect the A9*1 or A12*2 skid control ECU assembly connector.
      1. *1: w/o Vacuum Brake Booster
      2. *2: w/ Vacuum Brake Booster
    4. Disconnect the G82 shift control ECU connector.
    5. Disconnect the cable from the negative (-) battery terminal.
    6. Disconnect the L111 No. 3 semiconductor power integration ECU connector.
    7. Reconnect the cable from the negative (-) battery terminal.
    8. Measure the resistance according to the value(s) in the table below.

      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
    9. Connect the cable to the negative (-) battery terminal.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  21

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

      Refer to ON-VEHICLE INSPECTION [12/2017 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [12/2017 - 09/2018]  , or refer to  REMOVAL [09/2018 - 10/2020] 

    Result: 

    NG 

    REPLACE STOP LIGHT SWITCH ASSEMBLY. Refer to  REMOVAL [12/2017 - 09/2018]  , or refer to  REMOVAL [09/2018 - 10/2020] 

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