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DTC B1279: Rain Sensor Communication Stop: Procedure

  1. INSPECT FUSE (ECU-IG LH) 
    1. Remove the ECU-IG LH fuse from the main body ECU LH (cowl side junction block LH).
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      ECU-IG LH Always Below 1 Ω

    NG → REPLACE FUSE (ECU-IG LH) 

    OK: Go to next step 

  2. CHECK HARNESS AND CONNECTOR (OVERHEAD JUNCTION BLOCK - BATTERY AND BODY GROUND) 
    1. Disconnect the R5 connector.
      Fig 1: Identifying R5 Connector Teminals
      GTY283161Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the voltage and resistance according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      R5-21 (IG) - Body ground Engine switch on (IG) 11 to 14 V

      Standard Resistance

      Tester Connection Condition Specified Condition
      R5-39 (GND1) - Body ground Always Below 1 Ω

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (OVERHEAD JUNCTION BLOCK - BATTERY AND BODY GROUND) 

    OK: Go to next step 

  3. CHECK HARNESS AND CONNECTOR (RAIN SENSOR - BATTERY AND BODY GROUND) 
    1. Reconnect the R5 connector.
      Fig 2: Identifying R7 Connector Terminal
      GTY122259Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the R7 connector.
    3. Measure the voltage and resistance according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      R7-1 (SIG) - Body ground Engine switch on (IG) 11 to 14 V

      Standard Resistance

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

    NG → See step   5 

    OK: Go to next step 

  4. CHECK HARNESS AND CONNECTOR (COMMUNICATION LINE) 
    1. Disconnect the R7 and R5 connectors.
      Fig 3: Identifying R7 And R5 Connector Terminal
      GTY138306Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

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

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → See step   6 

  5. CHECK HARNESS AND CONNECTOR 
    1. Disconnect the R5 connector.
      Fig 4: Identifying R5 Connector Terminal
      GTY118630Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      R7-3 (ES) - R5-40 (GND2) Always Below 1Ω

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (OVERHEAD JUNCTION BLOCK - RAIN SENSOR) 

    OK → REPLACE OVERHEAD JUNCTION BLOCK 

  6. REPLACE RAIN SENSOR. Refer to  REMOVAL 
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