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Home >> Infiniti >> 2021 >> QX80 Premium Select, AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (DTCS) (4 Of 5) >> Engine (ECM) >> DTC P1078: EVT Control Position Sensor >> DTC Diagnosis Procedure
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DTC Diagnosis Procedure

  1. CHECK EXHAUST VALVE TIMING CONTROL POSITION SENSOR POWER SUPPLY CIRCUIT-I 
    1. Disconnect exhaust valve timing (EVT) control position sensor harness connector.
    2. Turn ignition switch ON.
    3. Check the voltage between exhaust valve timing control position sensor harness connector and ground.

      DTC

      EVT control position sensor

      Ground

      Voltage (V)

      Bank

      Connector

      Terminal

      P1078

      1

      F16

      1

      Ground

      Approx. 5

      P1084

      2

      F17

      1

    Is the inspection result normal?

    YES

    GO TO 2.

    NO

    Repair open circuit, short to ground in harness or connectors.

  2. CHECK EVT CONTROL POSITION SENSOR GROUND CIRCUIT FOR OPEN AND SHORT 
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Check the continuity between EVT control position sensor harness connector and ECM harness connector.

      DTC

      EVT control position sensor

      ECM

      Continuity

      Bank

      Connector

      Terminal

      Connector

      Terminal

      P1078

      1

      F16

      2

      F91

      45

      Existed

      P1084

      2

      F17

      2

      F92

      63
    4. Also check harness for short to power.

    Is the inspection result normal?

    YES

    GO TO 3.

    NO

    Repair open circuit, short to power in harness or connectors.

  3. CHECK EVT CONTROL POSITION SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
    1. Check the continuity between EVT control position sensor harness connector and ECM harness connector.

      DTC

      EVT control position sensor

      ECM

      Continuity

      Bank

      Connector

      Terminal

      Connector

      Terminal

      P1078

      1

      F16

      3

      F91

      41

      Existed

      P1084

      2

      F17

      3

      F92

      68
    2. Also check harness for short to ground and short to power.

    Is the inspection result normal?

    YES

    GO TO 4.

    NO

    Repair open circuit, short to ground or short to power in harness or connectors.

  4. CHECK EXHAUST VALVE TIMING CONTROL POSITION SENSOR 

    Refer to Component Inspection .

    Is the inspection result normal?

    YES

    GO TO 5.

    NO

    Replace malfunctioning exhaust valve timing control position sensor. Refer to TIMING CHAIN : Exploded View .

  5. CHECK CRANKSHAFT POSITION SENSOR 

    Refer to Component Inspection .

    Is the inspection result normal?

    YES

    GO TO 6.

    NO

    Replace crankshaft position sensor. Refer to CYLINDER BLOCK : Exploded View .

  6. CHECK CAMSHAFT POSITION SENSOR 

    Refer to Component Inspection .

    Is the inspection result normal?

    YES

    GO TO 7.

    NO

    Replace malfunctioning camshaft position sensor. Refer to CYLINDER BLOCK : Exploded View .

  7. CHECK CAMSHAFT SPROCKET (SIGNAL PLATE) 

    Check the following.

    • Accumulation of debris to the signal plate of camshaft sprocket (EXH)
      GNSJMBIA1571Z-571Courtesy of NISSAN NORTH AMERICA, INC.
    • Chipping signal plate of camshaft sprocket (EXH)

    Is the inspection result normal?

    YES

    GO TO 8.

    NO

    Remove debris and clean the signal plate of camshaft sprocket (EXH) or replace camshaft sprocket (EXH). Refer to CYLINDER BLOCK : Exploded View .

  8. CHECK INTERMITTENT INCIDENT 

    Refer to Inspection .

    INSPECTION END

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