FixVault
Home › Toyota › 2006 › Avalon XLS › Repair and Diagnosis › Electrical › Starter › Starting System › Entry And Start System › DTC B2278 Engine Switch Circuit Malfunction › Inspection Procedure

Inspection Procedure

  1. READ VALUE OF INTELLIGENT TESTER 
    1. Connect the intelligent tester to the DLC3.
    2. Turn the engine switch on (IG) and press the intelligent tester main switch on.
    3. Read the Data List according to the displays on the tester.

      PWR SOURCE CTRL (Power source control ECU): 

      DATA LIST (POWER SOURCE CONTROL ECU)

      Item Measurement Item / Display (Range) Normal Condition Diagnostic Note
      START SW1 Status of start switch 1 / ON or OFF ON: Engine switch ON (IG)
      OFF: Engine switch OFF (IG)      		 -
      START SW2 Status of start switch 2/ ON or OFF ON: Engine switch ON (IG)
      OFF: Engine switch OFF (IG)      		 -

      OK: 

      "ON" (engine switch on (IG)) appears on the screen 

      Result 

      RESULT REFERENCE

      Condition Proceed to
      NG C
      OK (When troubleshooting according to the PROBLEM SYMPTOM TABLE) B
      OK (When troubleshooting according to the DTC chart) A

    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. Disconnect the D21 switch connector.
    2. Measure the resistance according to the value(s) in the table below.

      Resistance 

      CONNECTOR TERMINALS RESISTANCE SPECIFICATION

      Terminal No. (Symbol) Switch Condition Specified value
      D21-2 (SS2) - D21-5 (GND) Free 10 kΩ or higher
      Pushed (Hold) Below 1 Ω
      D21-7 (SS1) - D21-5 (GND) Free 10 kΩ or higher
      Pushed (Hold) Below 1 Ω

    NG: REPLACE ENGINE SWITCH 

    Fig 1: Identifying Engine Switch Connector
    G04377205Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: Go to Next Step 

  3. CHECK WIRE HARNESS (ENGINE SWITCH - POWER SOURCE CONTROL ECU AND BODY GROUND) 
    1. Disconnect the D21 switch connector.
      Fig 2: Disconnecting D44 ECU Connector
      G04377206Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the D44 ECU connector.
      Fig 3: Identifying Engine Switch Connector
      G04377207Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Measure the resistance of the wire harness side connectors.

      Resistance 

      CONNECTOR TERMINALS RESISTANCE SPECIFICATION

      Terminal No. (Symbol) Specified Condition
      D21-7 (SS1) - D44-14 (SSW1) Below 1 Ω
      D21-2 (SS2) - D44-37 (SSW2) Below 1 Ω
      D21-5 (GND) - Body ground Below 1 Ω
      D21-7 (SS1) or D44-14 (SSW1) - Body ground 10 kΩ or higher
      D21-2 (SS2) or D44-37 (SSW2) - Body ground 10 kΩ or higher

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: REPLACE ENGINE SWITCH 

About FixVault