2004 Scion xA AutomaticFACTORY OEM SERVICE PROCEDURE

Audio Communication Line Check (Between Display Control Unit And Audio Unit)

WARNING: This page is about a different car, the 2004 Nissan Quest. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK POWER SUPPLY AND GROUND CIRCUIT 
    1. Check system of power supply and ground circuit audio unit. Refer to GROUND DISTRIBUTION & POWER DISTRIBUTION .

    OK or NG

    1. OK: GO TO 2.
    2. NG: Check the malfunctioning parts.
  2. CHECK HARNESS 
    1. Turn ignition switch OFF.
    2. Disconnect audio unit connector and display control unit connector.
    3. Check continuity between audio unit and display control unit.
      CONTINUITY SPECIFICATION

      Terminals Continuity
      Display control unit (+) Audio unit (-)
      Connector Terminal (Wire color) Connector Terminal (Wire color)
      M95 40 (B/R) M45 65 (B/R) Yes
      42 (BR) 66 (BR)
    4. Check continuity between display control unit and ground.
    CONTINUITY SPECIFICATION

    Terminals Continuity
    Display control unit(+) (-)
    Connector Terminal (Wire color)
    M95 40 (B/R) Ground No
    42 (BR)

    OK or NG

    1. OK: GO TO 3.
    2. NG: Repair harness or connector.
    Fig 1: Checking Continuity Between Display Control Unit And Ground
    G03501247Courtesy of NISSAN MOTOR CO., U.S.A.
  3. CHECK 1: AUDIO-TX COMMUNICATION SIGNAL 
    1. Connect display control unit connector.
    2. Turn ignition switch ON.
    3. Check voltage between display control unit harness connector M95 terminal 40 (B/R) and ground.
    1. Approx. 3.5 V or more. 

    OK or NG

    1. OK: GO TO 4.
    2. NG: Replace display control unit. Refer to REMOVAL AND INSTALLATION OF DISPLAY CONTROL UNIT .
      Fig 2: Checking Voltage Between Display Control Unit Harness Connector M95 Terminal 40
      G03501248Courtesy of NISSAN MOTOR CO., U.S.A.
  4. CHECK 2: AUDIO-RX COMMUNICATION SIGNAL 
    1. Turn ignition switch OFF.
    2. Disconnect display control unit connector.
    3. Connect audio unit connector.
    4. Turn ignition switch ON.
    5. Check voltage between audio unit harness connector M45 terminal 66 (BR) and ground.
    1. Approx. 3.5 V or more. 

    OK or NG

    1. OK: GO TO 5.
    2. NG: Replace audio unit. Refer to REMOVAL AND INSTALLATION FOR AUDIO UNIT .
      Fig 3: Checking Voltage Between Audio Unit Harness Connector M45 Terminal 66 (BR) And Ground
      G03501249Courtesy of NISSAN MOTOR CO., U.S.A.
  5. CHECK 3: AUDIO-TX COMMUNICATION SIGNAL 
    1. Turn ignition switch OFF.
    2. Connect display control unit connector.
    3. Turn ignition switch ON.
    4. Check signal between display control unit harness connector M95 terminal 40 (B/R) and ground with CONSULT-II or oscilloscope.
    1. 40 (B/R) - Ground: Refer to TERMINALS AND REFERENCE VALUE FOR DISPLAY CONTROL UNIT .

    OK or NG

    1. OK: GO TO 6.
    2. NG: Replace audio unit. Refer to REMOVAL AND INSTALLATION FOR AUDIO UNIT .
      Fig 4: Checking Signal Between Display Control Unit Harness Connector M95 Terminal 40 (B/R) And Ground
      G03501250Courtesy of NISSAN MOTOR CO., U.S.A.
  6. CHECK 4: AUDIO-RX COMMUNICATION SIGNAL 
    1. Turn ignition switch ON.
    2. Check signal between display control unit harness connector M95 terminal 42 (BR) and ground with CONSULT-II or oscilloscope.
    1. 42 (BR) - Ground: Refer to TERMINALS AND REFERENCE VALUE FOR DISPLAY CONTROL UNIT .
    Fig 5: Checking Signal Between Display Control Unit Harness Connector M95 Terminal 42 (BR) And Ground
    G03501251Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG

    1. OK: INSPECTION END.
    2. NG: Replace display control unit. Refer to REMOVAL AND INSTALLATION OF DISPLAY CONTROL UNIT .
Chapter Navigation
Return to Chapter: Navigation System
Factory Service Tools

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.

Shop Manual-Ready ToolsCompare Repair QuoteQuote Shield Pro

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.