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Home >> Lexus >> 2024 >> TX 350 Base, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 89 (Smart Access System (For Start) - Diagnostic Codes (2 Of 2) & Symptom Tests) >> SMART ACCESS SYSTEM WITH PUSH-BUTTON START (for Start Function, except Gasoline Model) >> Power Source Mode does not Change to ON (IG) [09/2023 - ] >> Procedure

Power Source Mode does not Change to ON (IG) [09/2023 - ]: Procedure

WARNING: This page is about a different car, the 2024 Lexus TX 550h+ and 2024 Lexus TX 500h. However, it is still accessible from the selected car via links, so may be relevant.
  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 [09/2023 - 12/2023]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [12/2023 - ] 

    Result: 

    See step  2

  2. CHECK HARNESS AND CONNECTOR (POWER DISTRIBUTION BOX ASSEMBLY - CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) AND BODY GROUND) 
    1. Disconnect the B7 certification ECU (smart key ECU assembly) connector.
    2. Disconnect the D62 and D63 power distribution box assembly connectors.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      D63-17 - B7-24 (IGPD) Always Below 1 Ω
      D62-10 - B7-11 (IGRD) Always Below 1 Ω
      D62-36 - Body ground Always Below 1 Ω
      D63-17 or B7-24 (IGPD) - Other terminals and body ground Always 10 kΩ or higher
      D62-10 or B7-11 (IGRD) - 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  3

  3. CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) 
    1. Connect the B7 certification ECU (smart key ECU assembly) connector.
      GTY1233876Courtesy 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
      B7-11 (IGRD) - Body ground Ignition switch ACC → Ignition switch ON 1 V or less → 9 V or higher
      B7-24 (IGPD) - Body ground Ignition switch ACC → Ignition switch ON 1 V or less → 9 V or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY). Refer to  REMOVAL [09/2023 - 12/2023]  , or refer to  REMOVAL [12/2023 - ] 

    Result: 

    OK 

    See step  4

  4. CHECK HARNESS AND CONNECTOR (POWER DISTRIBUTION BOX ASSEMBLY - POWER SOURCE) 
    1. Disconnect the B7 certification ECU (smart key ECU assembly) connector.
    2. Disconnect the B57, B58, D62 and D63 power distribution box assembly connectors.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      B57-1 - 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  5

  5. CHECK POWER DISTRIBUTION BOX ASSEMBLY 
    1. Remove the power distribution box assembly.

      Refer to REMOVAL [09/2023 - ]

    2. Remove the main body ECU (multiplex network body ECU) from the power distribution box assembly.
      GTY1241048Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component without harness connected
      (Power Distribution Box Assembly)
      - -
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      D63-17 - B58-14 Always Below 1 Ω
    4. Connect the auxiliary battery terminal (+) to the D62-10 terminal.
    5. Connect the auxiliary battery terminal (-) to the D62-36 terminal.
    6. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      B57-1 - D63-36 Auxiliary battery voltage applied between terminals D62-10 and D62-36 Below 1 Ω
      B57-1 - D62-39 Auxiliary battery voltage applied between terminals D62-10 and D62-36 Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE POWER DISTRIBUTION BOX ASSEMBLY. Refer to  REMOVAL [09/2023 - ] 

    Result: 

    OK 

    See step  6

  6. CHECK HARNESS AND CONNECTOR (POWER DISTRIBUTION BOX ASSEMBLY - IGP RELAY) 
    1. Remove the IGP NO. 1 relay from the No. 1 engine room relay block and No. 1 junction block assembly.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      B58-14 - IGP NO. 1 relay terminal 1 Always Below 1 Ω
      IGP NO. 1 relay terminal 2 - Body ground Always Below 1 Ω
      B58-14 or IGP NO. 1 relay terminal 1 - 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  7

  7. INSPECT IGP NO. 1 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
      GTY1018730Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 IGP NO. 1 Relay

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    NG 

    REPLACE IGP RELAY