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Vehicle Speed Signal Check for Display Control Unit

  1. VEHICLE SPEED OPERATION CHECK 

    Does speedmeter is operated normally?

    Yes or No

    1. Yes: GO TO 2.
    2. NO: Check combination meter trouble diagnosis. Refer to DIAGNOSIS FLOW .
  2. CHECK HARNESS 
    1. Turn ignition switch OFF.
    2. Disconnect display control unit connector and combination unified meter and A/C amp. connector.
    3. Check continuity between display control unit harness connector M75 terminal 16 (R/G) and unified meter and A/C amp. harness connector M56 terminal 26 (R/G).

      Continuity should exist. 

    4. Check continuity between display control unit harness connector M75 terminal 16 (R/G) and ground.

      Continuity should not exist. 

      Fig 1: Checking Continuity Between Display Control Unit Harness Connector M75 Terminal 16 (R/G) And Unified Meter And A/C Amp. Harness Connector M56 Terminal 26 (R/G)
      G02507774Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG

    1. OK: GO TO 3.
    2. NG: Repair harness or connector.
  3. CHECK VEHICLE SPEED SIGNAL 
    1. Connect display control unit and unified meter and A/C amp. connector.
    2. Start the engine.
    3. Drive vehicle at a constant speed.
    4. Check signal between display control unit harness connector M75 terminal 16 (R/G) and ground with CONSULT-II or oscilloscope.

      16 (R/G) - Ground: Refer to  Terminals and Reference Value for Display Control unit   . 

    OK or NG

    1. OK: Replace display control unit.
    2. NG: Check unified meter and A/C amp. system. Refer to VEHICLE SPEED SIGNAL INSPECTION
      Fig 2: Checking Signal Between Display Control Unit Harness Connector M75 Terminal 16 (R/G) And Ground With CONSULT-II Or Oscilloscope
      G02507775Courtesy of NISSAN MOTOR CO., U.S.A.