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Home › Lexus › 2008 › IS 350 › Repair and Diagnosis › Electrical › Starter › Starting (2GR-FSE) › Smart Access System With Push-Button Start › DTC B2278 Engine Switch Circuit Malfunction › Inspection Procedure

Inspection Procedure

  1. CHECK CONNECTORS 
    1. Check that the connectors are securely connected and the terminals are not deformed or loose.

      OK: 

      The connectors are securely connected and the terminals are not deformed or loose. 

    NG: REPAIR OR REPLACE CONNECTORS 

    OK: Go to Next Step 

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE CONTROL ECU - BODY GROUND) 
    1. Disconnect the J55 ECU connector.
    2. Measure the resistance according to the value (s) in the table below.

      Standard resistance 

      STANDARD RESISTANCE SPECIFICATION

      Tester Connection (Symbols) Condition Specified Condition
      J55-6 (GND2) - Body ground Always Below 1 Ω
      3. Fig 1: Identifying Terminal GND2 Of J55 Power Source Control ECU Connector
      G05829104Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to Next Step 

  3. INSPECT ENGINE SWITCH 
    1. Remove the engine switch.
      Fig 2: Identifying Engine Switch Connector
      G05829111Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the switch connector.
    3. Measure the resistance according to the value (s) in the table below.

      Standard resistance 

      STANDARD RESISTANCE SPECIFICATION

      Tester Connection (Symbols) 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

      HINT:

      This switch is a momentary type switch.

    NG: REPLACE ENGINE SWITCH 

    OK: Go to Next Step 

  4. CHECK WIRE HARNESS (ENGINE SWITCH - POWER SOURCE CONTROL ECU AND BODY GROUND) 
    1. Measure the resistance according to the value (s) in the table below.

      Standard resistance 

      STANDARD RESISTANCE SPECIFICATION

      Tester Connection (Symbols) Condition Specified Condition
      J31-7 (SS1) - J55-14 (SSW1) Always Below 1 Ω
      J31-2 (SS2) - J55-37 (SSW2) Always Below 1 Ω
      J31-5 (GND) - Body ground Always Below 1 Ω
      J31-7 (SS1) or J55-14 (SSW1) - Body ground Always 10 kΩ or higher
      J31-2 (SS2) or J55-37 (SSW2) - Body ground Always 10 kΩ or higher
      2. Fig 3: Identifying J31 Engine Switch And J55 Power Source Control ECU Connectors
      G05829112Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to Next Step 

  5. READ VALUE OF TECHSTREAM (START SWITCH 1 AND 2) 
    1. Reconnect the connectors.
    2. Connect Techstream to the DLC3.
    3. Turn the engine switch on (IG).
    4. Check the DATA LIST for proper functioning of the start switches 1 and 2.

      Body: 

      TESTER DISPLAY REFERENCE

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

      OK: 

      ON (engine switch on (IG)) and OFF (engine switch off) appear on the screen. 

    NG: REPLACE POWER SOURCE CONTROL ECU 

    OK: Go to Next Step 

  6. RECHECK FOR DTC 
    1. Delete the DTCs (See DIAGNOSIS SYSTEM  ).
    2. Check for DTCs again.

      OK: 

      DTC B2278 is not output. 

    NG: REPLACE POWER SOURCE CONTROL ECU 

    OK: CHECK INTERMITTENT PROBLEMS 

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