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Home › Lexus › 2008 › GS 350 AWD › Repair and Diagnosis › Accessories & Equipment › Entertainment Systems › Audio/Visual › Audio And Visual System › Microphone Circuit between Overhead Junction Block and Multi-display › Inspection Procedure

Inspection Procedure

  1. CHECK MULTI-DISPLAY 
    1. Check the waveform of the microphone using an oscilloscope.

      OK: Waveform that matches sound spoken into microphone is output. 

      WAVEFORM REFERENCE CHART

      Item Content
      Tester Connection K47-11 (MIN+) - K47-10 (MIN-)
      Tool Setting 0.2 V/DIV., 0.2 μs/DIV.
      Condition w/o LEXUS Link System:
      Engine switch on (ACC) and steering pad switch's "Voice" switch is pressed w/LEXUS Link System:
      Engine switch on (ACC) and overhead junction block's "PHONE" button pressed

    OK: REPLACE MULTI-DISPLAY 

    Fig 1: Identifying K47 Multi-Display Connector Terminals
    G05807719Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: Go to next step 

  2. CHECK LEXUS LINK SYSTEM 
    1. Check if the vehicle is equipped with the LEXUS link system.

      Result: 

      RESULT CHART

      Result Proceed to
      w/LEXUS Link System A
      w/o LEXUS Link System B

    B:  Go to step  7

    A: Go to next step 

  3. CHECK WIRE HARNESS (MAYDAY ECU - OVERHEAD JUNCTION BLOCK AND MULTI-DISPLAY) 
    1. Disconnect the U45 ECU connector.
    2. Disconnect the W6 junction block connector.
    3. Disconnect the K47 display connector.
    4. Measure the resistance of the wire harness side connectors.

      Standard resistance 

      RESISTANCE SPECIFIED CONDITION

      Tester Connection Specified Condition
      U45-7 (MCVD) - W6-19 (ACC) Below 1 Ω
      U45-8 (MCI+) - W6-3 (MI1+) Below 1 Ω
      U45-9 (MCI-) - W6-2 (MIC-) Below 1 Ω
      U45-17 (MCO+) - K47-11 (MIN+) Below 1 Ω
      U45-16 (MCO-) - K47-10 (MIN-) Below 1 Ω
      U45-19 (SG) - Body ground 10 kΩ or higher
      U45-7 (MCVD) - Body ground 10 kΩ or higher
      U45-8 (MCI+) - Body ground 10 kΩ or higher
      U45-9 (MCI-) - Body ground 10 kΩ or higher
      U45-17 (MCO+) - Body ground 10 kΩ or higher
      U45-18 (MCO-) - Body ground 10 kΩ or higher

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Fig 2: Identifying U45 ECU, W6 Junction Block And K47 Display Connector Terminals
    G05299559Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: Go to next step 

  4. CHECK MAYDAY ECU (MCVD VOLTAGE) 
    1. Reconnect the U45 ECU connector.
    2. Measure the voltage of the ECU.

      Standard voltage 

      VOLTAGE SPECIFIED CONDITION

      Tester Connection Condition Specified Condition
      U45-7 (MCVD) - Body ground Engine switch on (ACC) 4 to 6 V

    NG: REPLACE MAYDAY ECU 

    Fig 3: Identifying U45 ECU Connector Terminals
    G05299560Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: Go to next step 

  5. CHECK MAYDAY ECU 
    1. Reconnect the W6 junction block connector.
    2. Check the waveform of the mayday ECU using an oscilloscope.

      OK: Waveform that matches sound spoken into microphone is output. 

      WAVEFORM REFERENCE CHART

      Item Content
      Tester Connection U45-8 (MCI+) - U45-9 (MCI-)
      Tool Setting 0.2 V/DIV., 0.2 μs/DIV.
      Condition Engine switch on (ACC) and overhead junction block's "PHONE" button pressed
      Fig 4: Identifying U45 ECU Connector Terminals
      G05807722Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: REPLACE MAYDAY ECU 

    NG: Go to next step 

  6. CHECK MICROPHONE ASSEMBLY 
    1. Remove the microphone from the overhead junction block.
    2. Measure the resistance of the microphone.

      Standard resistance 

      RESISTANCE SPECIFIED CONDITION

      Tester Connection Specified Condition
      1 (MIC+) - 3 (MIC-) 1.9 to 2.2 kΩ

    NG: REPLACE MICROPHONE ASSEMBLY 

    Fig 5: Identifying Microphone Connector Terminals
    G05299562Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: PROCEED TO NEXT INSPECTION PROCEDURE SHOWN IN PROBLEM SYMPTOMS TABLE 

  7. CHECK WIRE HARNESS (OVERHEAD JUNCTION BLOCK - MULTI-DISPLAY) 
    1. Disconnect the W6 junction block connector.
    2. Disconnect the K47 display connector.
    3. Measure the resistance of the wire harness side connectors.

      Standard resistance 

      RESISTANCE SPECIFIED CONDITION

      Tester Connection Specified Condition
      K47-9 (MACC) - W6-19 (ACC) Below 1 Ω
      K47-11 (MIN+) - W6-3 (MI1+) Below 1 Ω
      K47-10 (MIN-) - W6-2 (MIC-) Below 1 Ω
      K47-9 (MACC) - Body ground 10 kΩ or higher
      K47-11 (MIN+) - Body ground 10 kΩ or higher
      K47-10 (MIN-) - Body ground 10 kΩ or higher

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Fig 6: Identifying W6 Junction Block And K47 Display Connector Terminals
    G05807724Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: Go to next step 

  8. CHECK MULTI-DISPLAY (MACC VOLTAGE) 
    1. Reconnect the K47 display connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard voltage 

      VOLTAGE SPECIFIED CONDITION

      Tester Connection Condition Specified Condition
      K47-9 (MACC) - Body ground Engine switch on (ACC) 4 to 6 V

    NG: REPLACE MULTI-DISPLAY 

    Fig 7: Identifying K47 Display Connector Terminals
    G05807725Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: Go to next step 

  9. CHECK MICROPHONE ASSEMBLY 
    1. Remove the microphone from the overhead junction block.
    2. Measure the resistance of the microphone.

      Standard resistance 

      RESISTANCE SPECIFIED CONDITION

      Tester Connection Specified Condition
      1 (MIC+) - 3 (MIC-) 1.9 to 2.2 kΩ

    NG: REPLACE MICROPHONE ASSEMBLY 

    Fig 8: Identifying Microphone Connector Terminals
    G05299562Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: PROCEED TO NEXT INSPECTION PROCEDURE SHOWN IN PROBLEM SYMPTOMS TABLE 

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