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Communication Line Inspection

WARNING: This page is about a different car, the 2003 Infiniti FX35. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK CONNECTOR 

    Check combination meter, unified meter and A/C amp. and terminals (combination meter-side, unified meter and A/C amp. side, and harness side) for looseness or bent terminals.

    OK or NG

    OK: GO TO 2.

    NG: Repair terminal or connector.

  2. CHECK METER/GAUGES VISUALLY 

    Does the pointer on the meter/gauge fluctuate at the engine start?

    Is the fluctuation acceptable?

    YES: GO TO 3.

    NO: GO TO  6 .

  3. CHECK CONTINUITY COMMUNICATION CIRCUIT (RX: COMBINATION METER) 
    1. Turn ignition switch OFF.
    2. Disconnect the combination meter connector and unified meter and A/C amp. connector.
    3. Check continuity between combination meter harness connector M20 terminal 13 (L/B) and unified meter and A/C amp. harness connector M55 terminal 19 (L/B).

      Continuity should exist. 

    4. Check continuity between combination meter harness connector M20 terminal 13 (L/B) and ground.
      Fig 1: Checking Continuity Between Combination Meter Harness Connector M20 Terminal 13 (L/B) & Ground
      G01178039Courtesy of NISSAN MOTOR CO., U.S.A.

    Continuity should not exist. 

    OK or NG

    OK: GO TO 4.

    NG: Repair harness or connector.

  4. CHECK VOLTAGE OF UNIFIED METER AND A/C AMP. 
    1. Connect unified meter and A/C amp. connector.
    2. Turn ignition switch ON.
    3. Check voltage between combination meter harness connector M20 terminal 13 (L/B) and ground.
      Fig 2: Checking Voltage Between Combination Meter Harness Connector M20 Terminal 13 (L/B) & Ground
      G01178040Courtesy of NISSAN MOTOR CO., U.S.A.

    Approx. 5V 

    OK or NG

    OK: GO TO 5.

    NG: Replace unified meter and A/C amp. Refer to REMOVAL AND INSTALLATION OF UNIFIED METER AND A/C AMP.  .

  5. CHECK VOLTAGE SIGNAL OF COMBINATION METER
    1. Turn ignition switch OFF and connect combination meter connector.
    2. Turn ignition switch ON.
    3. Check the signal between combination meter harness connector M20 terminal 13 (L/B) and ground with simple oscilloscope of CONSULT-II.
    Fig 3: Checking Signal Between Combination Meter Harness Connector M20 Terminal 13 (L/B) & Ground
    G01178042Courtesy of NISSAN MOTOR CO., U.S.A.
    Fig 4: Checking Oscilloscope Signal Between Combination Meter Harness Connector & Ground
    G01178041Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG

    OK: Replace unified meter and A/C amp. Refer to REMOVAL AND INSTALLATION OF UNIFIED METER AND A/C AMP.  .

    NG: Replace combination meter.

  6. CHECK CONTINUITY COMMUNICATION CIRCUIT (TX: COMBINATION METER) 
    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 14 (PU) and unified meter and A/C amp. harness connector M55 terminal 9 (PU).

      Continuity should exist. 

    4. Check continuity between combination meter harness connector M20 terminal 14 (PU) and ground.
      Fig 5: Checking Continuity Between Combination Meter Harness Connector M20 Terminal 14 (PU) & Ground
      G01178043Courtesy of NISSAN MOTOR CO., U.S.A.

      Continuity should not exist. 

    OK or NG

    OK: GO TO 7.

    NG: Repair harness or connector.

  7. CHECK VOLTAGE OF COMBINATION METER 
    1. Connect combination meter connector.
    2. Turn ignition switch ON.
    3. Check voltage between unified meter and A/C amp. harness connector M55 terminal 9 (PU) and ground.
      Fig 6: Checking Voltage Between Unified Meter & A/C Amp. Harness Connector M55 Terminal 9 (PU) & Ground
      G01178044Courtesy of NISSAN MOTOR CO., U.S.A.

      Approx. 5V 

    OK or NG

    OK: GO TO 8.

    NG: Replace combination meter.

  8. CHECK VOLTAGE SIGNAL OF UNIFIED METER AND A/C AMP. 
    1. Turn ignition switch OFF and connect unified meter and A/C amp. connector.
    2. Turn ignition switch ON.
    3. Check voltage signal between combination meter harness connector M20 terminal 14 (PU) and ground with simple oscilloscope of CONSULT-II.
    Fig 7: Checking Voltage Signal Between Combination Meter Harness Connector M20 Terminal 14 (PU) & Ground
    G01178046Courtesy of NISSAN MOTOR CO., U.S.A.
    Fig 8: Checking Voltage Signal Oscilloscope Pattern Between Combination Meter Harness Connector & Ground
    G01178045Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG

    OK: Replace combination meter.

    NG: Replace unified meter and A/C amp. Refer to REMOVAL AND INSTALLATION OF UNIFIED METER AND A/C AMP.  .

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