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Home >> Infiniti >> 2021 >> Q50 Pure, AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (DTCS) (5 Of 6) >> Engine (ECM) >> P2123 App Sensor >> DTC Diagnosis Procedure

DTC Diagnosis Procedure

  1. CHECK DTC PRIORITY 

    If DTC P2123 is displayed with DTC P0643, first perform the confirmation procedure (trouble diagnosis) for DTC P0643.

    Is applicable DTC detected?

    YES

    Perform diagnosis of applicable DTC. Refer to DTC Description .

    NO

    GO TO 2.

  2. CHECK APP SENSOR 1 POWER SUPPLY 
    1. Disconnect accelerator pedal position (APP) sensor harness connector.
    2. Turn ignition switch ON.
    3. Check the voltage between APP sensor harness connector and ground.

      +

      -

      Voltage (V)

      APP sensor

      Connector

      Terminal

      M124

      4

      Ground

      Approx. 5

    Is the inspection result normal?

    YES

    GO TO 4.

    NO

    GO TO 3.

  3. CHECK APP SENSOR 1 POWER SUPPLY CIRCUIT FOR OPEN AND SHORT 
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Check the continuity between APP sensor harness connector and ECM harness connector.

      +

      -

      Continuity

      APP sensor

      ECM

      Connector

      Terminal

      Connector

      Terminal

      M124

      4

      E152

      198

      Existed

    4. Also check harness for short to ground and short to power.

    Is the inspection result normal?

    YES

    Perform the trouble diagnosis for ECM power supply circuit. Refer to Diagnosis Procedure .

    NO

    Repair or replace error-detected parts.

  4. CHECK APP SENSOR 1 GROUND CIRCUIT FOR OPEN AND SHORT 
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Check the continuity between APP sensor harness connector and ECM harness connector.

      +

      -

      Continuity

      APP sensor

      ECM

      Connector

      Terminal

      Connector

      Terminal

      M124

      5

      E152

      203

      Existed

    4. Also check harness for short to ground and short to power.

    Is the inspection result normal?

    YES

    GO TO 5.

    NO

    Repair or replace error-detected parts.

  5. CHECK APP SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
    1. Check the continuity between APP sensor harness connector and ECM harness connector.

      +

      -

      Continuity

      APP sensor

      ECM

      Connector

      Terminal

      Connector

      Terminal

      M124

      6

      E152

      202

      Existed

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

    Is the inspection result normal?

    YES

    GO TO 6.

    NO

    Repair or replace error-detected parts.

  6. CHECK APP SENSOR 

    Refer to Component Inspection .

    Is the inspection result normal?

    YES

    INSPECTION END

    NO

    Replace accelerator pedal assembly. Refer to ACCELERATOR CONTROL SYSTEM : Removal & Installation .