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DTC B2278: Engine Switch Circuit Malfunction [09/2015 - ]: Procedure

  1. READ VALUE USING TECHSTREAM (ENGINE SWITCH) 
    1. Use the Data List to check if the engine switch is functioning properly.
      MAIN BODY

      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Start Switch1 Start switch 1/ON or OFF ON: Engine switch on (IG)
      OFF: Engine switch off      		 -
      Start Switch2 Start switch 2/ON or OFF ON: Engine switch on (IG)
      OFF: Engine switch off      		 -

      OK

      ON appears on the screen.

    Result:  NG

    NG 

    See step  3

    Result:  OK

    OK 

    See step  2

  2. CHECK ENGINE SWITCH (SWITCH CONDITION) 
    1. Ensure the key is inside the cabin.
    2. Check that the power source mode changes as shown below each time the engine switch is pushed.

      OK

      off → on (ACC) → on (IG) → off

    Result:  OK

    OK 

    SYSTEM IS OK 

    Result:  NG

    NG 

    GO TO POWER SOURCE MODE DOES NOT CHANGE 

    (Refer to Power Source Mode does not Change [09/2015 - ] )

  3. INSPECT ENGINE SWITCH 
    GTY674696Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Remove the engine switch (Refer to REMOVAL [09/2015 - ] ).
    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance

      Tester Connection Switch Condition Specified Condition
      7 (SS1) - 5 (GND) Pushed Below 1 Ω
      2 (SS2) - 5 (GND) Pushed Below 1 Ω
      7 (SS1) - 5 (GND) Not pushed 10 kΩ or higher
      2 (SS2) - 5 (GND) Not pushed 10 kΩ or higher

    Result:  NG

    NG 

    REPLACE ENGINE SWITCH 

    (Refer to REMOVAL [09/2015 - ] )

    Result:  OK

    OK 

    See step  4

  4. CHECK HARNESS AND CONNECTOR (ENGINE SWITCH - MAIN BODY ECU AND BODY GROUND) 
    GTY660235Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Disconnect the L36 engine switch connector.
    2. Disconnect the L13 main body ECU connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard resistance

      Tester Connection Condition Specified Condition
      L36-7 (SS1) - L13-17 (SSW1) Always Below 1 Ω
      L36-2 (SS2) - L13-16 (SSW2) Always Below 1 Ω
      L36-5 (GND) - Body ground Always Below 1 Ω
      L36-7 (SS1) or L13-17 (SSW1) - Body ground Always 10 kΩ or higher
      L36-2 (SS2) or L13-16 (SSW2) - Body ground Always 10 kΩ or higher

    Result:  OK

    OK 

    REPLACE MAIN BODY ECU 

    Result:  NG

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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