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Home >> Lexus >> 2007 >> IS 350 >> Repair and Diagnosis >> Accessories & Equipment >> Entertainment Systems >> Multiplex Communication >> Multiplex Communication System >> DTC B1279 Rain Sensor Communication Stop >> Inspection Procedure

Inspection Procedure

  1. INSPECT FUSE (ECU-IG LH) 
    1. Remove the ECU-IG LH fuse from the cowl side J/B LH.
    2. Measure the resistance of the fuse.

      Standard resistance: 

      Below 1 Ω 

    NG: REPLACE FUSE 

    OK: Go to next step. 

  2. CHECK WIRE HARNESS (OVERHEAD J/B - BATTERY AND BODY GROUND) 
    1. Disconnect the R5 connector.
    2. Measure the voltage and resistance of the wire harness side connector.

      Standard voltage 

      TESTER CONNECTION AND SPECIFIED CONDITION TABLE

      Tester Connection Condition Specified Condition
      IG (R5-21) - Body ground Engine switch on (IG) 10 to 14 V

      Standard resistance 

      TESTER CONNECTION AND SPECIFIED CONDITION TABLE

      Tester Connection Specified Condition
      GND2 (R5-40) - Body ground Below 1 ohms

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Fig 1: Identifying Overhead J/B Connector Terminals
    G04051887Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: Go to next step. 

  3. CHECK WIRE HARNESS (RAIN SENSOR - BATTERY AND BODY GROUND) 
    1. Disconnect the R7 connector.
    2. Measure the voltage and resistance of the wire harness side connector.

      Standard voltage 

      TESTER CONNECTION AND SPECIFIED CONDITION TABLE

      Tester Connection Condition Specified Condition
      SIG (R7-1) - Body ground Engine switch on (IG) 10 to 14 V

      Standard resistance 

      TESTER CONNECTION AND SPECIFIED CONDITION TABLE

      Tester Connection Specified Condition
      ES (R7-3) - Body ground Below 1 ohms

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Fig 2: Identifying Rain Sensor Connector Terminals
    G04051888Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: Go to next step. 

  4. CHECK RESISTANCE OF COMMUNICATION LINE 
    1. Disconnect the R7 and R5 ECU connectors.
    2. Measure the resistance between the specified terminals on the wire harness side connectors.

      Standard resistance 

      TESTER CONNECTION AND SPECIFIED CONDITION TABLE

      Tester Connection Specified Condition
      MPX (R7-2) - MPX1 (R5-37) Below 1 ohms

      Result 

      RESULT DESCRIPTION TABLE

      Result Proceed to
      Both are OK A
      One is OK B
      Both are NG C

    B: REPAIR OR REPLACE HARNESS OR CONNECTOR OR REPLACE RAIN SENSOR 

    C: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Fig 3: Identifying Overhead J/B Connector Terminals
    G04051889Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    A: REPLACE RAIN SENSOR 

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