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Home >> Lexus >> 2020 >> LC 500h >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Anti-Theft Systems >> 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 (ACC) [01/2017 - 05/2023] >> Procedure
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Power Source Mode does not Change to ON (ACC) [01/2017 - 05/2023]: Procedure

  1. CHECK FOR DTC 
    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 / Smart Access, Power Source Control / Trouble Codes.
    5. Check for DTCs.

      Body Electrical > Power Source Control > Trouble Codes 

      Body Electrical > Smart Access > Trouble Codes 

      Result

      Result Proceed to
      DTCs are not output A
      Smart access system with push-button start (for Start Function) DTCs are output B

    Result: 

    GO TO DIAGNOSTIC TROUBLE CODE CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART [01/2017 - 06/2019]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [06/2019 - 04/2020]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [04/2020 - 05/2023] 

    Result: 

    See step  2

  2. CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) 
    1. Measure the voltage according to the value(s) in the table below.
      GTY836985Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Certification ECU (Smart Key ECU Assembly))

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      P66-16 (ACCD) - Body ground Power switch off → Power switch on (ACC) 1 V or less → 8.5 V or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [01/2017 - 05/2023] 

    Result: 

    OK 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (DRIVER SIDE JUNCTION BLOCK ASSEMBLY - CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) AND BODY GROUND) 
    1. Disconnect the P66 certification ECU (smart key ECU assembly) connector.
    2. Disconnect the 3B and 3F driver side junction block assembly connectors.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      P66-16 (ACCD) - 3B-17 Always Below 1 Ω
      3B-6 - Body ground Always Below 1 Ω
      P66-16 (ACCD) or 3B-17 - Other terminals and body ground Always 10 kΩ or higher
    4. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      3F-1 - Body ground Power switch off 11 to 14 V
    5. Reconnect the P66 certification ECU (smart key ECU assembly) connector.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  4

  4. CHECK DRIVER SIDE JUNCTION BLOCK ASSEMBLY (ACC D RELAY) 
    1. Remove the driver side junction block assembly.

      Refer to REMOVAL [01/2017 - 05/2023]

    2. Reconnect the all driver side junction block assembly connectors.
    3. Measure the voltage according to the value(s) in the table below.
      GTY801458Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Driver Side Junction Block Assembly)
      - -

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      3A-43 - Body ground Power switch on (ACC) 11 to 14 V
      3A-18 - Body ground Power switch on (ACC) 8.5 to 14 V
      3D-32 - Body ground Power switch on (ACC) 8.5 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE DRIVER SIDE JUNCTION BLOCK ASSEMBLY. Refer to  REMOVAL [01/2017 - 05/2023] 

    Result: 

    OK 

    See step  5

  5. CHECK HARNESS AND CONNECTOR (PASSENGER SIDE JUNCTION BLOCK ASSEMBLY - DRIVER SIDE JUNCTION BLOCK ASSEMBLY AND BODY GROUND) 
    1. Disconnect the 3A driver side junction block assembly connector.
    2. Disconnect the 4B, 4A and 4F passenger side junction block assembly connectors.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      3A-18 - 4B-26 Always Below 1 Ω
      4A-9 - Body ground Always Below 1 Ω
      3A-18 or 4B-26 - Other terminals and body ground Always 10 kΩ or higher
    4. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      4F-1 - Body ground Power switch off 11 to 14 V
    5. Reconnect the 3A driver side junction block assembly connector.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  6

  6. CHECK PASSENGER SIDE JUNCTION BLOCK ASSEMBLY (ACC P RELAY) 
    1. Remove the passenger side junction block assembly.

      Refer to REMOVAL [01/2017 - 05/2023]

    2. Reconnect the all passenger side junction block assembly connectors.
    3. Measure the voltage according to the value(s) in the table below.
      GTY778377Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Passenger Side Junction Block Assembly)
      - -

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      4B-27 - Body ground Power switch on (ACC) 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE PASSENGER SIDE JUNCTION BLOCK ASSEMBLY. Refer to  REMOVAL [01/2017 - 05/2023] 

    Result: 

    OK 

    See step  7

  7. CHECK HARNESS AND CONNECTOR (DRIVER SIDE JUNCTION BLOCK ASSEMBLY - LUG-ACC RELAY AND BODY GROUND) 
    1. Disconnect the 3D driver side junction block assembly connector.
    2. Remove the LUG-ACC relay.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      3D-32 - LUG-ACC relay installation terminal 1 Always Below 1 Ω
      LUG-ACC relay installation terminal 2 - Body ground Always Below 1 Ω
      3D-32 or LUG-ACC relay installation terminal 1 - Other terminals and body ground Always 10 kΩ or higher
    4. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      LUG-ACC relay installation terminal 3 - Body ground Power switch off 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  8

  8. INSPECT LUG-ACC RELAY 
    1. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      3 - 5 Auxiliary battery voltage applied between terminals 1 and 2 Below 1 Ω
      Auxiliary battery voltage not applied between terminals 1 and 2 10 kΩ or higher
      GTY464377Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 LUG-ACC Relay

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [01/2017 - 04/2020]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [04/2020 - 05/2023] 

    Result: 

    NG 

    REPLACE LUG-ACC RELAY