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Home >> Lexus >> 2024 >> TX 350 Base, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 96 (Smart Access System (For Start) - Diagnostic Codes (1 Of 2)) >> SMART ACCESS SYSTEM WITH PUSH-BUTTON START (for Start Function, except Gasoline Model) >> DTC B2278-62: Engine/Power Switch Signal Compare Failure [12/2023 - ] >> Procedure

DTC B2278-62: Engine/Power Switch Signal Compare Failure [12/2023 - ]: 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. READ VALUE USING GTS (PUSH START SWITCH 1) 
    1. Read the Data List according to the display on the GTS.

      Body Electrical > Power Source Control > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Push Start Switch 1 Power switch 1 status OFF or ON OFF: Power switch not pressed
      • If the power switch is pressed for a short time, the display may not change.
      • Use this item to determine if the power switch input signal is malfunctioning.

      Body Electrical > Power Source Control > Data List 

      Tester Display
      Push Start Switch 1

      OK

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

      Result

      Result Proceed to
      The value of Push Start Switch 1 is OFF A
      The value of Push Start Switch 1 is not OFF B

    Result: 

    B 

    See step  13

    Result: 

    A 

    See step  2

  2. READ VALUE USING GTS (PUSH START SWITCH 1) 
    1. Read the Data List according to the display on the GTS.

      Body Electrical > Power Source Control > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Push Start Switch 1 Power switch 1 status OFF or ON ON: Power switch pressed
      • If the power switch is pressed for a short time, the display may not change.
      • Use this item to determine if the power switch input signal is malfunctioning.

      Body Electrical > Power Source Control > Data List 

      Tester Display
      Push Start Switch 1

      OK

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

      Result

      Result Proceed to
      The value of Push Start Switch 1 is ON A
      The value of Push Start Switch 1 is not ON B

    Result: 

    B 

    See step  13

    Result: 

    A 

    See step  3

  3. READ VALUE USING GTS (PUSH START SWITCH 2) 
    1. Read the Data List according to the display on the GTS.

      Body Electrical > Power Source Control > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Push Start Switch 2 Power switch 2 status OFF or ON OFF: Power switch not pressed
      • If the power switch is pressed for a short time, the display may not change.
      • Use this item to determine if the power switch input signal is malfunctioning.

      Body Electrical > Power Source Control > Data List 

      Tester Display
      Push Start Switch 2

      OK

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

      Result

      Result Proceed to
      The value of Push Start Switch 2 is OFF A
      The value of Push Start Switch 2 is not OFF B

    Result: 

    B 

    See step  13

    Result: 

    A 

    See step  4

  4. READ VALUE USING GTS (PUSH START SWITCH 2) 
    1. Read the Data List according to the display on the GTS.

      Body Electrical > Power Source Control > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Push Start Switch 2 Power switch 2 status OFF or ON ON: Power switch pressed
      • If the power switch is pressed for a short time, the display may not change.
      • Use this item to determine if the power switch input signal is malfunctioning.

      Body Electrical > Power Source Control > Data List 

      Tester Display
      Push Start Switch 2

      OK

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

      Result

      Result Proceed to
      The value of Push Start Switch 2 is ON A
      The value of Push Start Switch 2 is not ON B

    Result: 

    B 

    See step  13

    Result: 

    A 

    See step  5

  5. READ VALUE USING GTS (PUSH START SWITCH 3) 
    1. Read the Data List according to the display on the GTS.

      Body Electrical > Power Source Control > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Push Start Switch 3 Power switch 3 status OFF or ON OFF: Power switch not pressed
      • If the power switch is pressed for a short time, the display may not change.
      • Use this item to determine if the power switch input signal is malfunctioning.

      Body Electrical > Power Source Control > Data List 

      Tester Display
      Push Start Switch 3

      OK

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

      Result

      Result Proceed to
      The value of Push Start Switch 3 is OFF A
      The value of Push Start Switch 3 is not OFF B

    Result: 

    B 

    See step  13

    Result: 

    A 

    See step  6

  6. READ VALUE USING GTS (PUSH START SWITCH 3) 
    1. Read the Data List according to the display on the GTS.

      Body Electrical > Power Source Control > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Push Start Switch 3 Power switch 3 status OFF or ON ON: Power switch pressed
      • If the power switch is pressed for a short time, the display may not change.
      • Use this item to determine if the power switch input signal is malfunctioning.

      Body Electrical > Power Source Control > Data List 

      Tester Display
      Push Start Switch 3

      OK

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

      Result

      Result Proceed to
      The value of Push Start Switch 3 is ON A
      The value of Push Start Switch 3 is not ON B

    Result: 

    B 

    See step  13

    Result: 

    A 

    See step  7

  7. READ VALUE USING GTS (PUSH START SWITCH 1) 
    1. According to the display on the GTS, read the Data List while wiggling the wire harness.

      Body Electrical > Power Source Control > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Push Start Switch 1 Power switch 1 status OFF or ON OFF: Power switch not pressed
      • If the power switch is pressed for a short time, the display may not change.
      • Use this item to determine if the power switch input signal is malfunctioning.

      Body Electrical > Power Source Control > Data List 

      Tester Display
      Push Start Switch 1

      OK

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

      Result

      Result Proceed to
      The value of Push Start Switch 1 is OFF A
      The value of Push Start Switch 1 is not OFF B

    Result: 

    B 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    A 

    See step  8

  8. READ VALUE USING GTS (PUSH START SWITCH 1) 
    1. According to the display on the GTS, read the Data List while wiggling the wire harness.

      Body Electrical > Power Source Control > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Push Start Switch 1 Power switch 1 status OFF or ON ON: Power switch pressed
      • If the power switch is pressed for a short time, the display may not change.
      • Use this item to determine if the power switch input signal is malfunctioning.

      Body Electrical > Power Source Control > Data List 

      Tester Display
      Push Start Switch 1

      OK

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

      Result

      Result Proceed to
      The value of Push Start Switch 1 is ON A
      The value of Push Start Switch 1 is not ON B

    Result: 

    B 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    A 

    See step  9

  9. READ VALUE USING GTS (PUSH START SWITCH 2) 
    1. According to the display on the GTS, read the Data List while wiggling the wire harness.

      Body Electrical > Power Source Control > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Push Start Switch 2 Power switch 2 status OFF or ON OFF: Power switch not pressed
      • If the power switch is pressed for a short time, the display may not change.
      • Use this item to determine if the power switch input signal is malfunctioning.

      Body Electrical > Power Source Control > Data List 

      Tester Display
      Push Start Switch 2

      OK

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

      Result

      Result Proceed to
      The value of Push Start Switch 2 is OFF A
      The value of Push Start Switch 2 is not OFF B

    Result: 

    B 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    A 

    See step  10

  10. READ VALUE USING GTS (PUSH START SWITCH 2) 
    1. According to the display on the GTS, read the Data List while wiggling the wire harness.

      Body Electrical > Power Source Control > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Push Start Switch 2 Power switch 2 status OFF or ON ON: Power switch pressed
      • If the power switch is pressed for a short time, the display may not change.
      • Use this item to determine if the power switch input signal is malfunctioning.

      Body Electrical > Power Source Control > Data List 

      Tester Display
      Push Start Switch 2

      OK

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

      Result

      Result Proceed to
      The value of Push Start Switch 2 is ON A
      The value of Push Start Switch 2 is not ON B

    Result: 

    B 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    A 

    See step  11

  11. READ VALUE USING GTS (PUSH START SWITCH 3) 
    1. According to the display on the GTS, read the Data List while wiggling the wire harness.

      Body Electrical > Power Source Control > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Push Start Switch 3 Power switch 3 status OFF or ON OFF: Power switch not pressed
      • If the power switch is pressed for a short time, the display may not change.
      • Use this item to determine if the power switch input signal is malfunctioning.

      Body Electrical > Power Source Control > Data List 

      Tester Display
      Push Start Switch 3

      OK

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

      Result

      Result Proceed to
      The value of Push Start Switch 3 is OFF A
      The value of Push Start Switch 3 is not OFF B

    Result: 

    B 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    A 

    See step  12

  12. READ VALUE USING GTS (PUSH START SWITCH 3) 
    1. According to the display on the GTS, read the Data List while wiggling the wire harness.

      Body Electrical > Power Source Control > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Push Start Switch 3 Power switch 3 status OFF or ON ON: Power switch pressed
      • If the power switch is pressed for a short time, the display may not change.
      • Use this item to determine if the power switch input signal is malfunctioning.

      Body Electrical > Power Source Control > Data List 

      Tester Display
      Push Start Switch 3

      OK

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

      Result

      Result Proceed to
      The value of Push Start Switch 3 is ON A
      The value of Push Start Switch 3 is not ON B

    Result: 

    A 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2023 - ] 

    Result: 

    B 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  13. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - POWER SWITCH) 

    Pre-procedure1

    • Disconnect the D38 certification ECU (smart key ECU assembly) connector.
    • Disconnect the D116 power switch connector.
    • Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      D38-19 (SSW1) - D116-12 (SS1) Always Below 1 Ω Ω
      D38-27 (SSW2) - D116-6 (SS2) Always Below 1 Ω Ω
      D38-23 (SSW3) - D116-11 (SS3) Always Below 1 Ω Ω
      D38-30 (AGND) - D116-3 (GND) Always Below 1 Ω Ω
      D38-19 (SSW1) or D116-12 (SS1) - Other terminals and body ground Always 10 kΩ or higher kΩ
      D38-27 (SSW2) or D116-6 (SS2) - Other terminals and body ground Always 10 kΩ or higher kΩ
      D38-23 (SSW3) or D116-11 (SS3) - Other terminals and body ground Always 10 kΩ or higher kΩ
      D38-30 (AGND) or D116-3 (GND) - Other terminals and body ground Always 10 kΩ or higher kΩ

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • None

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  14

  14. INSPECT POWER SWITCH 

    for T24A-FTS: Refer to INSPECTION [09/2023 - ]

    for 2GR-FXS: Refer to INSPECTION [12/2023 - ]

    Result

    Proceed to
    OK
    NG

    Result: 

    OK 

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

    Result: 

    NG 

    REPLACE POWER SWITCH 

    for T24A-FTS: Refer to REMOVAL [09/2023 - ]

    for 2GR-FXS: Refer to REMOVAL [12/2023 - ]

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