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DTC B2278: Engine Switch Circuit Malfunction (08/2010 - 08/2011): Procedure

  1. READ VALUE USING TECHSTREAM (START SWITCH 1, 2) 
    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

      When the engine switch is turned on (IG), ON is displayed on the Techstream.

    NG → See step   4 

    OK: Go to next step 

  2. CHECK WHETHER DTC OUTPUT RECURS 
    1. Clear the DTCs. Refer to DTC CHECK / CLEAR .
    2. Turn the engine switch on (IG), and check whether DTC B2278 is output.
      RESULT

      Result Proceed to
      No DTC output A
      DTC B2278 output B

    B → REPLACE MAIN BODY ECU (COWL SIDE JUNCTION BLOCK LH) 

    A → See step   3 

  3. USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING 
  4. INSPECT ENGINE SWITCH 
    Fig 1: Identifying Engine Switch Connector
    GTY109967Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Disconnect the E18 engine switch connector.
    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

    NG → See step   6 

    OK: Go to next step 

  5. CHECK HARNESS AND CONNECTOR (ENGINE SWITCH - MAIN BODY ECU AND BODY GROUND) 
    Fig 2: Identifying Engine Switch Connector Terminal And Main Body ECU Connector Terminal
    GTY110164Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Disconnect the E1 main body ECU connector.
    2. Disconnect the E18 engine switch connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      E1-17 (SSW1) - E18-7 (SS1) Always Below 1 Ω
      E1-16 (SSW2) - E18-2 (SS2) Always Below 1 Ω
      E18-5 (GND) - Body ground Always Below 1 Ω
      E1-17 (SSW1) or E18-7 (SS1) - Body ground Always 10 kΩ or higher
      E1-16 (SSW2) or E18-2 (SS2) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → REPLACE MAIN BODY ECU (COWL SIDE JUNCTION BLOCK LH) 

  6. REPLACE ENGINE SWITCH. Refer to  REMOVAL 
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