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Home › Lexus › 2006 › IS 250 AWD › Repair and Diagnosis › Electrical › Starter › Starting (4GR-FSE) › Smart Access System With Push-Button Start › DTC B2278 Engine Switch Circuit Malfunction › Inspection Procedure

Inspection Procedure

  1. READ VALUE OF INTELLIGENT TESTER (START SWITCH 1 and 2) 
    1. Connect the intelligent tester (with CAN VIM) to the DLC3.
    2. Turn the engine switch on (IG).
    3. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST.
    4. Check the DATA LIST for proper functioning of the start switches 1 and 2.

    Power source control ECU: 

    INTELLIGENT TESTER - DATA LIST

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

    Result 

    RESULT REFERENCE

    Result Proceed to
    OK (When troubleshooting according to the DTC table) A
    OK (When troubleshooting according to the PROBLEM SYMPTOMS TABLE) B
    NG C

    B: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE 

    C: Go to step   2 

    A: REPLACE POWER SOURCE CONTROL ECU 

  2. INSPECT ENGINE SWITCH 
    1. Remove the engine switch.
      2. Fig 1: Identifying Engine Switch
      G04044954Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance of the switch.

    Standard resistance 

    ENGINE SWITCH

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

    NG: REPLACE ENGINE SWITCH 

    OK: Go To Next Step 

  3. CHECK WIRE HARNESS (ENGINE SWITCH - POWER SOURCE CONTROL ECU AND BODY GROUND) 
    1. Disconnect the J31 switch connector.
    2. Disconnect the J55 ECU connector.
    3. Measure the resistance of the wire harness side connectors.

    Standard resistance 

    ENGINE SWITCH - POWER SOURCE CONTROL ECU AND BODY GROUND

    Tester Connection (Symbols) Specified Condition
    J31-7 (SS1) - J55-14 (SSW1) Below 1 ohms
    J31-2 (SS2) - J55-37 (SSW2) Below 1 ohms
    J31-5 (GND) - Body ground Below 1 ohms
    J31-7 (SS1) or J55-14 (SSW1) - Body ground 10 k ohms or higher
    J31-2 (SS2) or J55-37 (SSW2) - Body ground 10 k ohms or higher
    Fig 2: Identifying J31 Switch Connector
    G04044955Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: REPLACE POWER SOURCE CONTROL ECU 

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