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Home >> Toyota >> 2005 >> Prius >> Repair and Diagnosis >> Body & Frame >> Ignition Switch/Steering Lock >> Push Button Start System - Diagnostics >> DTC B2278: Main Switch (Power Switch) Malfunction >> Inspection Procedure
July 1: So it begins. Don't worry, this is not in the correct legal jurisdiction!

Inspection Procedure

  1. READ DATA LIST (START SWITCH 1 and 2) 
    1. Connect the hand-held tester (with CAN VIM) to the DLC3.
    2. Turn the power switch ON (IG) and press the hand-held tester main switch ON.
    3. Read the DATA LIST according to the displays on the tester.

      Power source control ECU: 

      Fig 1: Power Source Control ECU - Data List
      G02617858Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: ON (power switches 1 and 2 are ON (IG)) appears on the screen 

    1. NG: Go to step 2 
    2. OK: GO TO NEXT STEP 

      REPLACE POWER SOURCE CONTROL ECU 

  2. CHECK WIRE HARNESS (POWER SWITCH - POWER SOURCE CONTROL ECU AND BODY GROUND) 
    1. Disconnect the P11 power switch connector.
    2. Disconnect the P6 ECU connector.
    3. Measure the resistance of the wire harness side connectors.

      Standard: 

      TESTER CONNECTION AND SPECIFIED CONDITION CHART

      Tester Connection Specified Condition
      P11-5 (SS1) - P6-14 (SSW1) Below 1 Ω
      P11-7 (SS2) - P6-37 (SSW2) Below 1 Ω
      P11-6 - Body ground Below 1 Ω
      P11-5 (SS2) or P6-14 (SSW1) - Body ground 10 kΩ higher
      P11-7 (SS2) or P6-37 (SSW2) - Body ground 10 kΩ higher
      Fig 2: Disconnecting P6 ECU Connector
      G02617859Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG: REPAIR OR REPLACE HARNESS AND CONNECTOR 
    2. OK: GO TO NEXT STEP 
  3. INSPECT POWER SWITCH (See  INSPECTION   ) 
    1. NG: REPLACE POWER SWITCH 
    2. OK: GO TO NEXT STEP 

      REPLACE POWER SOURCE CONTROL ECU