ECD SYSTEM (w/o DPF), Diagnostic DTC:P1251

DTC Code DTC Name
P1251 Turbocharger / Supercharger Overboost Condition (Too High)

DESCRIPTION

Tech Tips

Refer to DTC P0046 Click here.

Refer to DTC P00AF Click here.

P1251
DTC Detection Drive Pattern DTC Detection Condition Trouble Area
Vehicle being driven The turbo motor driver detects an overcurrent caused by the DC motor being stuck (1 trip detection logic).

  • Turbocharger sub-assembly

  • Turbo motor driver

  • Turbo motor driver power source

  • VN turbo link stuck malfunction

  • Extremely low battery voltage (P0560 stored simultaneously)

  • ECM
Related Data List
DTC No. Data List
P1251

  • MAP

  • Target Booster Pressure

If DTC P1251 is stored, the following symptoms may appear:


WIRING DIAGRAM

Refer to DTC P0046 Click here.

Refer to DTC P00AF Click here.

INSPECTION PROCEDURE

Tech Tips

Read freeze frame data using the intelligent tester. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, and other data from the time the malfunction occurred.

Note

After replacing the ECM, the new ECM needs registration Click here and initialization Click here.

PROCEDURE


  1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P1251)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON and turn the tester on.

    3. Enter the following menus: Powertrain / Engine / DTC.

    4. Read the DTCs.

      Result
      Display (DTC Output) Proceed to
      P1251 A
      P1251 and other DTCs B

    B

    GO TO DTC CHART Click here

    A

  2. INSPECT TURBOCHARGER SUB-ASSEMBLY (for Bank 1 and/or Bank 2)


    1. A015AHDE04

      Check the motor movement when turning the ignition switch to ON, when starting the engine and then when turning the ignition switch off.

      OK
      Motor moves as shown in the illustration.

    NG

    Click here

    OK

  3. CHECK WHETHER DTC OUTPUT RECURS (DTC P1251)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON and turn the tester on.

    3. Enter the following: Powertrain / Engine / DTC / Clear.

    4. Clear DTCs Click here.

    5. Turn the ignition switch off.

    6. Start the engine and warm it up.

    7. Drive the vehicle.

    8. Enter the following menus: Powertrain / Engine / DTC.

    9. Read the DTCs.

      Result
      Display (DTC Output) Proceed to
      P1251 A
      No output B

    A

    REPLACE ECM Click here

    B

    END

  4. INSPECT TURBO MOTOR DRIVER (POWER SOURCE CIRCUIT)


    1. A015CQKE02

      Disconnect the turbo motor driver connector.

    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      for Bank 1
      Tester Connection Condition Specified Condition
      Turbo motor driver connector-3 (+B) - Turbo motor driver connector-4 (GND) Ignition switch ON 11 to 14 V
      for Bank 2
      Tester Connection Condition Specified Condition
      Turbo motor driver connector-3 (+B2) - Turbo motor driver connector-4 (GND2) Ignition switch ON 11 to 14 V

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      for Bank 1
      Tester Connection Condition Specified Condition
      Turbo motor driver connector-4 (GND) - Body ground Always Below 1 Ω
      for Bank 2
      Tester Connection Condition Specified Condition
      Turbo motor driver connector-4 (GND2) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR Click here

    OK

  5. CHECK HARNESS AND CONNECTOR (TURBO MOTOR DRIVER - ECM)


    1. Disconnect the turbo motor driver connector.

    2. A0159OJE01

      Disconnect the ECM connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for Open)
      for LHD
      Tester Connection Condition Specified Condition
      C45-49 (VNTO) - B-4 (VNTO) Always Below 1 Ω
      C45-50 (VNTI) - B-3 (VNTI) Always Below 1 Ω
      C45-47 (VNO2) - D-4 (VNO2) Always Below 1 Ω
      C45-48 (VNI2) - D-3 (VNI2) Always Below 1 Ω
      for RHD
      Tester Connection Condition Specified Condition
      C46-49 (VNTO) - B-4 (VNTO) Always Below 1 Ω
      C46-50 (VNTI) - B-3 (VNTI) Always Below 1 Ω
      C46-47 (VNO2) - D-4 (VNO2) Always Below 1 Ω
      C46-48 (VNI2) - D-3 (VNI2) Always Below 1 Ω
      Standard Resistance (Check for Short)
      for LHD
      Tester Connection Condition Specified Condition
      C45-49 (VNTO) or B-4 (VNTO) - Body ground Always 10 kΩ or higher
      C45-50 (VNTI) or B-3 (VNTI) - Body ground Always 10 kΩ or higher
      C45-47 (VNO2) or D-4 (VNO2) - Body ground Always 10 kΩ or higher
      C45-48 (VNI2) or D-3 (VNI2) - Body ground Always 10 kΩ or higher
      for RHD
      Tester Connection Condition Specified Condition
      C46-49 (VNTO) or B-4 (VNTO) - Body ground Always 10 kΩ or higher
      C46-50 (VNTI) or B-3 (VNTI) - Body ground Always 10 kΩ or higher
      C46-47 (VNO2) or D-4 (VNO2) - Body ground Always 10 kΩ or higher
      C46-48 (VNI2) or D-3 (VNI2) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR Click here

    OK

  6. CHECK HARNESS AND CONNECTOR (DC MOTOR - TURBO MOTOR DRIVER)


    1. A0157YAE03

      Disconnect the DC motor connector.

    2. Disconnect the turbo motor driver connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for Open)
      for Bank 1
      Tester Connection Condition Specified Condition
      C90-1 (M-) - Turbo motor driver connector-2 (M-) Always Below 1 Ω
      C90-2 (M+) - Turbo motor driver connector-1 (M+) Always Below 1 Ω
      for Bank 2
      Tester Connection Condition Specified Condition
      z67-1 (M2-) - Turbo motor driver connector-2 (M2-) Always Below 1 Ω
      z67-2 (M2+) - Turbo motor driver connector-1 (M2+) Always Below 1 Ω
      Standard Resistance (Check for Short)
      for Bank 1
      Tester Connection Condition Specified Condition
      C90-1 (M-) or Turbo motor driver connector-2 (M-) - Body ground Always 10 kΩ or higher
      C90-2 (M+) or Turbo motor driver connector-1 (M+) - Body ground Always 10 kΩ or higher
      for Bank 2
      Tester Connection Condition Specified Condition
      z67-1 (M2-) or Turbo motor driver connector-2 (M2-) - Body ground Always 10 kΩ or higher
      z67-2 (M2+) or Turbo motor driver connector-1 (M2+) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR Click here

    OK

  7. REPLACE TURBO MOTOR DRIVER (for Bank 1 and/or Bank 2)


    1. Replace the turbo motor driver (for Bank 1 and/or Bank 2) Click here.


    NEXT

  8. CHECK WHETHER DTC OUTPUT RECURS (DTC P1251)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON and turn the tester on.

    3. Enter the following menus: Powertrain / Engine / DTC / Clear.

    4. Clear the DTCs Click here.

    5. Turn the ignition switch off.

    6. Start the engine and warm it up.

    7. Drive the vehicle.

    8. Enter the following menus: Powertrain / Engine / DTC.

    9. Read the DTCs.

      Result
      Display (DTC Output) Proceed to
      P1251 A
      No output B

    B

    END

    A

  9. REPLACE TURBOCHARGER SUB-ASSEMBLY (for Bank 1 and/or Bank 2) (DC MOTOR)


    1. Replace the turbocharger sub-assembly (for Bank 1 or Bank 2) Click here.


    NEXT

    CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED Click here

  10. REPAIR OR REPLACE HARNESS OR CONNECTOR


    NEXT

    CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED Click here

  11. REPLACE ECM


    1. Replace the ECM Click here.


    NEXT

  12. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED


    1. Connect the intelligent tester to the DLC3.

    2. Clear the DTCs Click here.

    3. Turn the ignition switch off.

    4. Start the engine and warm it up.

    5. Run the engine with a heavy load at a mid to high engine speed.

    6. Confirm that the DTC is not output again.

      Tech Tips

      Perform the following procedure using the tester to determine whether or not the DTC judgment has been carried out.


      1. Enter the following menus: Powertrain / Engine / Utility / All Readiness.

      2. Input DTC P1251.

      3. Check that STATUS is NORMAL. If STATUS is INCOMPLETE or UNKNOWN, increase the time spent running the engine with a heavy load at a mid to high engine speed.


    NEXT

    END