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Inspection Procedure

NOTE: When using the Techstream with the engine switch off to troubleshoot:
Connect the Techstream to the vehicle, and turn a courtesy switch on and off at 1.5 second intervals until communication between the Techstream and vehicle begins.
  1. READ VALUE USING TECHSTREAM (LIN COMMUNICATION) 
    1. Using the Techstream, read the "Data List".

      Body No. 5: 

      ITEM RANGE REFERENCE

      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      LIN Communication Status of LIN communication/Without or With Without: No connection
      With: Connection      		 -
      Curr Comm Rain Sensor Current communication with rain sensor/OK or Stop OK: Connection
      Stop: No connection      		 -

      OK: 

      Techstream displays "With" and "OK" 

      NG: Go to step 2 

      OK: USE SIMULATION METHOD TO CHECK  (See HOW TO PROCEED WITH TROUBLESHOOTING )

  2. CHECK HARNESS AND CONNECTOR (FRONT LIGHT ECU - RAIN SENSOR) 
    Fig 1: Identifying Terminals Of A50 ECU And X8 Sensor Connectors
    G04947022Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Disconnect the A50 ECU connector.
    2. Disconnect the X8 sensor connector.
    3. Measure the resistance and voltage according to the value(s) in the table below.

      Standard resistance 

      SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      A50-9 (LIN) - X8-3 (MPX) Always Below 1 Ω
      A50-9 (LIN) or X8-3 (MPX) - Body ground Always 10 kΩ or higher

      Standard voltage 

      VOLTAGE SPECIFICATION

      Tester Connection Condition Specified Condition
      A50-9 (LIN) or X8-3 (MPX) - Body ground Always Below 1 V

      NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

      OK: CHECK RAIN SENSOR (BATTERY VOLTAGE AND GROUND) 

  3. CHECK RAIN SENSOR (BATTERY VOLTAGE AND GROUND) 
    1. Disconnect the X8 sensor connector.
    2. Measure the resistance and voltage according to the value(s) in the table below.

      Standard resistance 

      SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      X8-1 (ES) - Body ground Always Below 1 Ω

      Standard voltage 

      VOLTAGE SPECIFICATION

      Tester Connection Switch Condition Specified Condition
      X8-4 (SIG) - Body ground Engine Switch off Below 1 V
      X8-4 (SIG) - Body ground Engine Switch on (IG) 11 to 14 V
      Fig 2: Identifying X8 Sensor Connector Terminal
      G04947023Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

      OK: Go to next step 

  4. REPLACE RAIN SENSOR 
    1. Temporarily replace the rain sensor with a new or normally functioning one (see RAIN SENSOR ).
  5. READ VALUE USING TECHSTREAM (LIN COMMUNICATION) 
    1. Using the Techstream, read the "Data List".

      Body No. 5: 

      ITEM RANGE REFERENCE

      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      LIN Communication Status of LIN communication/Without or With Without: No connection
      With: Connection      		 -
      Curr Comm Rain Sensor Current communication with rain sensor/OK or Stop OK: Connection
      Stop: No connection      		 -

      OK: 

      Techstream displays "With" and "OK". 

      NG: REPLACE FRONT LIGHT ECU (FRONT CONTROLLER) 

      OK: END (RAIN SENSOR IS DEFECTIVE) 

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