Mike's Workshop Manuals: Service manuals for every vehicle
Home >> Infiniti >> 2024 >> Q50 Luxe, AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (DTCS) (7 Of 7) >> Engine (ECM) >> P2578 TC/SC Speed Sensor A >> DTC Diagnosis Procedure

DTC Diagnosis Procedure

  1. COMPONENT FUNCTION CHECK 

    SYMBOL With CONSULT

    1. Start the engine.
    2. On CONSULT screen, select "ENGINE" >> "Data monitor" >> "TC/SC SPEED B1".
    3. Check that the values displayed on "TC/SC SPEED B1" is 14, 000 - 26, 000 rpm when maintaining 3, 000 rpm with no load condition.

    Is the inspection result normal?

    YES>>

    INSPECTION END

    NO>>

    GO TO 2.

  2. CHECK TURBOCHARGER SPEED SENSOR (BANK 1) INSTALLATION CONDITION 

    Check that the turbocharger speed sensor (bank 1) is installed correctly with no float and disconnection.

    Is the inspection result normal?

    YES>>

    GO TO 3.

    NO>>

    Install the sensor correctly.

  3. CHECK TURBOCHARGER SPEED SENSOR 

    Check the turbocharger speed sensor. Refer to Component Inspection . Is the inspection result normal?

    YES>>

    GO TO 4.

    NO>>

    Replace turbocharger speed sensor (bank 1). Refer to TURBOCHARGER : Exploded View .

  4. CHECK TURBOCHARGER SPEED SENSOR (BANK 1) POWER SUPPLY 
    1. Turn ignition switch OFF.
    2. Disconnect turbocharger speed sensor (bank 1) harness connector.
    3. Turn ignition switch ON.
    4. Check the voltage between turbocharger speed sensor (bank 1) harness connector and ground.
      + - Voltage
      (Approx.)
      Turbocharger speed sensor (bank 1)
      Connector Terminal
      F141 1 Ground 5 V

    Is the inspection result normal?

    YES>>

    GO TO 6.

    NO>>

    GO TO 5.

  5. CHECK TURBOCHARGER SPEED SENSOR (BANK 1) POWER SUPPLY CIRCUIT 
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Check the continuity between turbocharger speed sensor (bank 1) harness connector and ECM harness connector.
      Turbocharger speed sensor (bank 1) ECM Continuity
      Connector Terminal Connector Terminal
      F141 1 F142 131 Existed
    4. Also check harness for short to ground and short to power.

    Is the inspection result normal?

    YES>>

    INSPECTION END

    NO>>

    Repair or replace error-detected parts.

  6. CHECK TURBOCHARGER SPEED SENSOR (BANK 1) GROUND CIRCUIT 
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Check the continuity between turbocharger speed sensor (bank 1) harness connector and ECM harness connector.
      Turbocharger speed sensor (bank 1) ECM Continuity
      Connector Terminal Connector Terminal
      F141 3 F142 98 Existed
    4. Also check harness for short to power.

    Is the inspection result normal?

    YES>>

    GO TO 7.

    NO>>

    Repair or replace error-detected parts.

  7. CHECK TURBOCHARGER SPEED SENSOR (BANK 1) INPUT SIGNAL CIRCUIT 
    1. Check the continuity between turbocharger speed sensor (bank 1) harness connector and ECM harness connector.
      Turbocharger speed sensor (bank 1) ECM Continuity
      Connector Terminal Connector Terminal
      F141 2 F142 137 Existed
    2. Also check harness for short to power.

    Is the inspection result normal?

    YES>>

    GO TO 8.

    NO>>

    Repair or replace error-detected parts.

  8. CHECK ECM GROUND CIRCUIT 
    1. Disconnect ECM harness connectors.
    2. Check the continuity between ECM harness connector and ground.
      ECM - Continuity
      Connector Terminal
      F143 3 Ground Existed
      F142 87
      88
      E152 199
      201
      204

    Is the inspection result normal?

    YES>>

    INSPECTION END

    NO>>

    Repair or replace error-detected parts.

scientia non olet · About Mike's Workshop Manuals