2004 Nissan-Datsun Sentra SE-RFACTORY 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 Murano. 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 circuit audio unit. Refer to "POWER SUPPLY CIRCUIT INSPECTION ".

    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 CHECK CHART

      Terminals Continuity
      Display control unit Audio unit
      Connector Terminal (Wire color) Connector Terminal (Wire color)
      M43 40 (R/G) M46 23 (R/G) Yes
      42 (R/Y) 21 (R/Y)
    4. Check continuity between display control unit and ground.
      CONTINUITY CHECK CHART

      Terminals Continuity
      Display control unit Ground
      Connector Terminal (Wire color)
      M43 40 (R/G) No
      42 (R/Y)
      Fig 1: Checking Continuity Between Display Control Unit And Ground
      G03492574Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG

    1. OK: GO TO 3.
    2. NG: Repair harness or connector.
  3. CHECK1: AUDIO TX COMMUNICATION SIGNAL 
    1. Connect audio unit connector.
    2. Turn ignition switch ON.
    3. Check voltage between audio unit harness connector M46 terminal 23 (R/G) and ground.

      Approx. 4V 

      Fig 2: Checking Voltage Between Audio Unit Harness Connector And Ground
      G03492575Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG

    1. OK: GO TO 4.
    2. NG: Replace audio unit.
  4. CHECK2: AUDIO RX COMMUNICATION SIGNAL 
    1. Turn ignition switch OFF.
    2. Disconnect audio unit connector, and connect display control unit connector.
    3. Turn ignition switch ON.
    4. Check voltage between display control unit harness connector M43 terminal 42 (R/Y) and ground.

      Approx. 4V 

      Fig 3: Checking Voltage Between Display Control Unit Harness Connector And Ground
      G03492576Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG

    1. OK: GO TO 5.
    2. NG: Replace display control unit.
  5. CHECK3: AUDIO TX COMMUNICATION SIGNAL 
    1. Turn ignition switch OFF.
    2. Connect audio unit connector.
    3. Turn ignition switch ON.
    4. Check signal between display control unit harness connector M43 terminal 40 (R/G) and ground with CONSULT-II or oscilloscope.

      40 (R/G) - Ground: Refer to " TERMINALS AND REFERENCE VALUE FOR DISPLAY CONTROL UNIT   ". 

      Fig 4: Checking Signal Between Display Control Unit Harness Connector And Ground
      G03492577Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG

    1. OK: GO TO 6. 
    2. NG: Replace display control unit. 
  6. CHECK4: AUDIO RX COMMUNICATION SIGNAL 
    1. Turn ignition switch ON.
    2. Check signal between display control unit harness connector "M43" terminal 42 (R/Y) and ground with CONSULT-II or oscilloscope.

      42 (R/Y) - Ground: Refer to " TERMINALS AND REFERENCE VALUE FOR DISPLAY CONTROL UNIT   ". 

    OK or NG

    Fig 5: Checking Signal Between Display Control Unit Harness Connector
    G03492578Courtesy of NISSAN MOTOR CO., U.S.A.
    1. OK: GO TO 7.
    2. NG: Replace audio unit.
  7. CHECK SELF-DIAGNOSIS OF DCU 
    1. Turn ignition switch OFF.
    2. Replace display control unit.
    3. Turn ignition switch ON.
    4. Start self-diagnosis of DCU, and check the self-diagnosis result.

    OK or NG

    1. OK: INSPECTION END.
    2. NG: Replace audio unit.
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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.

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