FixVault

Vehicle Speed Signal Inspection

Symptom: Speedometer and ODO/trip meter indication is malfunction.

  1. CHECK COMBINATION METER INPUT SIGNAL 
    1. Connect CONSULT-II, and start engine.
    2. Select "METER A/C AMP" on CONSULT-II.
    3. Using "SPEED METER" on "DATA MONITOR", compare the value of "DATA MONITOR" with speedometer pointer of combination meter.

    OK or NG 

    OK : Perform self-diagnosis of ABS actuator and electric unit (control unit). Refer to "CONSULT-II FUNCTIONS (VDC) ".

    NG : GO TO 2.

    Fig 1: Identifying Combination Meter Input Signal
    G04078447Courtesy of NISSAN MOTOR CO., U.S.A.
  2. CHECK UNIFIED METER AND A/C AMP. OUTPUT SIGNAL 
    1. Drive vehicle at approximately 40 km/h (25 MPH).
    2. Check voltage signal between unified meter and A/C amp. harness connector M56 terminal 26 and ground.
      NOTE: Maximum voltage may be 5 V due to specifications (connected units).

      26 - Ground: 

      Fig 2: Identifying Unified Meter And A/C Amp
      G04078448Courtesy of NISSAN MOTOR CO., U.S.A.
      Fig 3: Identifying Waveform Signal Between Terminal 26 And Ground
      G04078449Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    OK : GO TO 3.

    NG-1 : If monitor indicates "0 V" constantly, perform the following.

    1. Check each unit inputting vehicle speed signal (8 pulse), harness and connector between each unit and unified meter and A/C amp.
    2. Repair or replace malfunctioning part.

    NG-2 : If monitor indicates "5 V" or "12 V" constantly, replace unified meter and A/C amp. Refer to "REMOVAL AND INSTALLATION OF UNIFIED METER AND A/C AMP. ".

  3. CHECK CONTINUITY BETWEEN COMBINATION METER AND UNIFIED METER AND A/C AMP. 
    1. Turn ignition switch OFF.
    2. Disconnect combination meter connector and unified meter and A/C amp. connector.
    3. Check continuity between combination meter harness connector M20 terminal 1 and unified meter and A/C amp. harness connector M56 terminal 26.

      1 - 26 : Continuity should exist. 

    OK or NG 

    OK : Replace combination meter.

    NG : Repair harness or connector.

    Fig 4: Identifying Continuity Between Combination Meter Harness Connector M20 Terminal 1 And Unified Meter And A/C Amp
    G04078450Courtesy of NISSAN MOTOR CO., U.S.A.