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Home >> Lexus >> 2021 >> LS 500 Base, 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 (ACC) [10/2023 - ] >> Procedure

Power Source Mode does not Change to ON (ACC) [10/2023 - ]: Procedure

  1. CHECK FOR DTC 
    1. Using the GTS, check for certification ECU (smart key ECU assembly) 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 [10/2023 - ] 

    Result: 

    See step  2

  2. CHECK HARNESS AND CONNECTOR (POWER DISTRIBUTION BOX ASSEMBLY - POWER SOURCE) 
    1. Disconnect the 8H power distribution box assembly connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      8H-1 - Body ground Ignition switch off 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  3

  3. CHECK POWER DISTRIBUTION BOX ASSEMBLY (ACC RELAY) 
    1. Remove the power distribution box assembly.

      Refer to REMOVAL [10/2023 - ]

    2. Remove the main body ECU (multiplex network body ECU) from the power distribution box assembly.
    3. Connect the auxiliary battery terminal (+) to the 8B-38 terminal.
    4. Connect the auxiliary battery terminal (-) to the 8B-36 terminal.
      GTY1209125Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component without harness connected
      (Power Distribution Box Assembly)
      - -
    5. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      8H-1 - 8B-12 Auxiliary battery voltage applied between terminals 8B-38 and 8B-36 Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    NG 

    REPLACE POWER DISTRIBUTION BOX ASSEMBLY. Refer to  REMOVAL [10/2023 - ]