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Home >> Lexus >> 2011 >> RX 350 AWD >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Infotainment >> Navigation System (For DVD) (Diagnostic Codes & Symptom Tests) >> NAVIGATION SYSTEM (for DVD) >> DTC B15D0: MOST Communication Malfunction >> Procedure

DTC B15D0: MOST Communication Malfunction: Procedure

  1. CONFIRM MODEL 
    1. Choose the model to be inspected.

      Result

      Model Proceed to
      for 15 speakers A
      except 15 speakers B

    B → See step   3 

    A: Go to next step 

  2. CONFIRM SYMPTOMS 
    1. Engine switch off.
    2. Turn the engine switch on (ACC) and check if the audio system activates and if the speakers operate.

      HINT: 

      • Choose a source such as radio so that sound can be output from the speakers.
      • If sound from the speakers is low, turn up the volume.

      Result

      Model Proceed to
      The audio system activates when the engine switch is turned on (ACC) but the sound stops being output when the amplifier output exceeds a certain level. A
      Even after the engine switch is turned on (ACC), the audio system does not activate and sound is not output from the speakers. B

      HINT: 

      • If a short occurs in a speaker circuit, the sound from the corresponding speaker will be low or almost impossible to hear. If the volume is turned up in this situation, to prevent excessive current flow due to the short circuit, the stereo component amplifier assembly stops operating when its output exceeds a certain level. When the operation of the stereo component amplifier assembly stops, the navigation system will not function normally. This is because MOST communication will stop due to the shut down of the amplifier causing an error in the MOST network. The stereo component amplifier assembly will start operating again when the engine switch is turned off and back on (ACC) again. However, the amplifier will stop operating again if its output exceeds a certain level.
      • When the stereo component amplifier assembly stops operating and a malfunction occurs in the navigation system due to a short in a speaker circuit, this DTC will be stored. In this case, check each speaker circuit and repair or replace malfunctioning parts, and then recheck for DTCs.

    B → See step   3 

    A → See step   23 

  3. CHECK MOST LINE CHECK 
    1. Display the "MOST Line Check" screen. Refer to DTC CHECK / CLEAR .
      Fig 1: MOST Line Check Screen
      GTY351933Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      1. Check the result on the "MOST Line Check" screen.

        Result

        Result Proceed to
        "NCON" is displayed for "AMP". A
        "NCON" is displayed for "R-TOUCH". B
        "NCON" is displayed for "AUDIO". C
        "OK" is displayed for all items. D

        HINT: 

        • When "NCON" is displayed for more than 1 item, proceed to the step for the device that has the smallest node position number.
        • The "MOST Line Check" screen can be displayed only when DTC B15D0 is stored.
        TEXT IN ILLUSTRATION

        *1 Node position number for devices that use MOST communication
        *2 Device Name
        *3 Result

    B → See step   7 

    C → See step   10 

    D → See step   13 

    A: Go to next step 

  4. CHECK MOST COMMUNICATION CONNECTOR 
    1. Check the MOST communication line connector.
      1. Check the MOST communication line connectors of the radio receiver assembly and stereo component amplifier assembly. Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE .
    2. Display the "MOST Line Check" screen and check the result. Refer to DTC CHECK / CLEAR .

      Result

      Result Proceed to
      "NCON" is displayed for "AMP". A
      The screen cannot be changed to the "MOST Line Check" screen. B

      HINT: 

      When the malfunction in the MOST network is repaired, the screen cannot be changed to the "MOST Line Check" screen.

    B → END 

    A: Go to next step 

  5. CHECK HARNESS AND CONNECTOR (WAKE UP SIGNAL) 
    1. Disconnect the stereo component amplifier assembly connector.
      Fig 2: Stereo Component Amplifier Assembly Connector
      GTY353575Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      O15-3 (WUI) - Body ground Engine switch on (ACC) 4.5 V or higher
      TEXT IN ILLUSTRATION

      *1 Front view of wire harness connector
      (to Stereo Component Amplifier Assembly)

    NG → See step   6 

    OK → See step   18 

  6. CHECK HARNESS AND CONNECTOR 
    1. Disconnect the stereo component amplifier assembly connector.
      Fig 3: Stereo Component Amplifier Assembly Connector
      GTY353575Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the radio receiver assembly connector.
      Fig 4: Radio Receiver Assembly Connector
      GTY349382Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      O15-3 (WUI) - G12-26 (WUO) Always Below 1 Ω
      O15-3 (WUI) - Body ground Always 10 kΩ or higher
      TEXT IN ILLUSTRATION

      *1 Front view of wire harness connector
      (to Stereo Component Amplifier Assembly)
      *2 Front view of wire harness connector
      (to Radio Receiver Assembly)

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → See step   16 

  7. CHECK MOST COMMUNICATION CONNECTOR 
    1. Check the MOST communication line connector.
      1. Check the MOST communication line connectors of the display and navigation module display and remote touch. Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE .
    2. Display the "MOST Line Check" screen and check the result. Refer to DTC CHECK / CLEAR .

      Result

      Result Proceed to
      "NCON" is displayed for "R-TOUCH". A
      The screen cannot be changed to the "MOST Line Check" screen. B

      HINT: 

      When the malfunction in the MOST network is repaired, the screen cannot be changed to the "MOST Line Check" screen.

    B → END 

    A: Go to next step 

  8. CHECK HARNESS AND CONNECTOR (WAKE UP SIGNAL) 
    1. Disconnect the remote touch connector.
      Fig 5: Remote Touch Connector
      GTY348694Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      G14-8 (WUI) - Body ground Engine switch on (ACC) 4.5 V or higher
      TEXT IN ILLUSTRATION

      *1 Front view of wire harness connector
      (to Remote Touch)

    NG → See step   9 

    OK → See step   20 

  9. CHECK HARNESS AND CONNECTOR 
    1. Disconnect the remote touch connector.
      Fig 6: Remote Touch Connector
      GTY348694Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the display and navigation module display connector.
      Fig 7: Display And Navigation Module Display Connector
      GTY348511Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G14-8 (WUI) - G6-8 (WUO) Always Below 1 Ω
      G14-8 (WUI) - Body ground Always 10 kΩ or higher
      TEXT IN ILLUSTRATION

      *1 Front view of wire harness connector
      (to Remote Touch)
      *2 Front view of wire harness connector
      (to Display and Navigation Module Display)

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → See step   19 

  10. CHECK MOST COMMUNICATION CONNECTOR 
    1. Check the MOST communication line connector.
      1. Check the MOST communication line connectors of the radio receiver assembly and remote touch. Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE .
    2. Display the "MOST Line Check" screen and check the result. Refer to DTC CHECK / CLEAR .

      Result

      Result Proceed to
      "NCON" is displayed for "AUDIO". A
      The screen cannot be changed to the "MOST Line Check" screen. B

      HINT: 

      When the malfunction in the MOST network is repaired, the screen cannot be changed to the "MOST Line Check" screen.

    B → END 

    A: Go to next step 

  11. CHECK HARNESS AND CONNECTOR (WAKE UP SIGNAL) 
    1. Disconnect the radio receiver assembly connector.
      Fig 8: Radio Receiver Assembly Connector
      GTY349383Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      G12-12 (WUI) - Body ground Engine switch on (ACC) 4.5 V or higher
      TEXT IN ILLUSTRATION

      *1 Front view of wire harness connector
      (to Radio Receiver Assembly)

    NG → See step   12 

    OK → See step   21 

  12. CHECK HARNESS AND CONNECTOR 
    1. Disconnect the radio receiver assembly connector.
      Fig 9: Radio Receiver Assembly Connector
      GTY349383Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the remote touch connector.
      Fig 10: Remote Touch Connector
      GTY358167Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G12-12 (WUI) - G14-4 (WUO) Always Below 1 Ω
      G12-12 (WUI) - Body ground Always 10 kΩ or higher
      TEXT IN ILLUSTRATION

      *1 Front view of wire harness connector
      (to Radio Receiver Assembly)
      *2 Front view of wire harness connector
      (to Remote Touch)

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → See step   17 

  13. CHECK HARNESS AND CONNECTOR 
    1. Disconnect the display and navigation module display connector.
      Fig 11: Display And Navigation Module Display Connector
      GTY358136Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the remote touch connector.
      Fig 12: Remote Touch Connector
      GTY348691Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Disconnect the radio receiver assembly connector.
      Fig 13: Radio Receiver Assembly Connector
      GTY349384Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    4. Disconnect the stereo component amplifier assembly connector.
      Fig 14: Stereo Component Amplifier Assembly Connector
      GTY353578Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    5. Measure the resistance between the display and navigation module display and stereo component amplifier assembly according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G6-1 (MI+) - O15-6 (MO+) Always Below 1 Ω
      G6-5 (MI-) - O15-12 (MO-) Always Below 1 Ω
      G6-2 (SLDI) - O15-11 (SLDO) Always Below 1 Ω
      G6-1 (MI+) - Body ground Always 10 kΩ or higher
      G6-5 (MI-) - Body ground Always 10 kΩ or higher
      G6-2 (SLDI) - Body ground Always 10 kΩ or higher
    6. Measure the resistance between the display and navigation module display and remote touch according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G6-3 (MO+) - G14-6 (MI+) Always Below 1 Ω
      G6-7 (MO-) - G14-5 (MI-) Always Below 1 Ω
      G6-6 (SLDO) - G14-7 (SLDI) Always Below 1 Ω
      G6-3 (MO+) - Body ground Always 10 kΩ or higher
      G6-7 (MO-) - Body ground Always 10 kΩ or higher
      G6-6 (SLDO) - Body ground Always 10 kΩ or higher
    7. Measure the resistance between the remote touch and radio receiver assembly according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G14-1 (MO+) - G12-9 (MI+) Always Below 1 Ω
      G14-2 (MO-) - G12-23 (MI-) Always Below 1 Ω
      G14-3 (SLDO) - G12-10 (SLDI) Always Below 1 Ω
      G14-1 (MO+) - Body ground Always 10 kΩ or higher
      G14-2 (MO-) - Body ground Always 10 kΩ or higher
      G14-3 (SLDO) - Body ground Always 10 kΩ or higher
    8. Measure the resistance between the radio receiver assembly and stereo component amplifier assembly according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G12-11 (MO+) - O15-4 (MI+) Always Below 1 Ω
      G12-25 (MO-) - O15-10 (MI-) Always Below 1 Ω
      G12-24 (SLDI) - O15-5 (SLDI) Always Below 1 Ω
      G12-11 (MO+) - Body ground Always 10 kΩ or higher
      G12-25 (MO-) - Body ground Always 10 kΩ or higher
      G12-24 (SLDI) - Body ground Always 10 kΩ or higher
      TEXT IN ILLUSTRATION

      *1 Front view of wire harness connector
      (to Display and Navigation Module Display)
      *2 Front view of wire harness connector
      (to Remote Touch)
      *3 Front view of wire harness connector
      (to Radio Receiver Assembly)
      *4 Front view of wire harness connector
      (to Stereo Component Amplifier Assembly)

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  14. CHECK DTC 
    1. Clear the DTCs. Refer to DTC CHECK / CLEAR .
    2. Recheck for DTCs and check if the same DTC is output again.

      OK

      No DTCs are output.

    NG → See step   22 

    OK → See step   15 

  15. USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING 
  16. REPLACE RADIO RECEIVER ASSEMBLY. Refer to  REMOVAL 
  17. REPLACE REMOTE TOUCH (REMOTE OPERATION BOARD). Refer to  DISASSEMBLY 
  18. REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY. Refer to  REMOVAL 
  19. REPLACE DISPLAY AND NAVIGATION MODULE DISPLAY. Refer to  REMOVAL 
  20. REPLACE REMOTE TOUCH (REMOTE OPERATION BOARD). Refer to  DISASSEMBLY 
  21. REPLACE RADIO RECEIVER ASSEMBLY. Refer to  REMOVAL 
  22. REPLACE DISPLAY AND NAVIGATION MODULE DISPLAY. Refer to  REMOVAL 
  23. GO TO AUDIO AND VISUAL SYSTEM (w/ Navigation System). Refer to  Speaker Circuit 
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