ECD SYSTEM, Diagnostic DTC:P0234, P0299, P1251

DTC Code DTC Name
P0234 Turbocharger / Supercharger Overboost Condition
P0299 Turbocharger / Supercharger Underboost
P1251 Turbocharger / Supercharger Overboost Condition (Too High)

DESCRIPTION

DTC No. DTC Detection Condition Trouble Area
P0234 Actual turbocharger pressure is deviated 100 kPa (750 mmHg, 29.5 in.Hg) or more from the simulated target pressure for 60 seconds

  • Open or short in VN turbo control circuit

  • Turbocharger

  • Turbocharger actuator

  • EGR valve assembly

  • MAF meter

  • Turbo pressure sensor

  • Vacuum hose

  • Exhaust system is clogged

  • ECM
P0299 Actual turbocharger pressure is deviated -50 kPa (-375 mmHg, -14.8 in.Hg) to -100 kPa (-750 mmHg, -29.5 in.Hg) or more from the simulated target pressure for 50 seconds

  • Open or short in VN turbo control circuit

  • Turbocharger

  • Turbocharger actuator

  • EGR valve assembly

  • MAF meter

  • Turbo pressure sensor

  • Exhaust system and intake system are modified or clogged

  • ECM
P1251 Actual turbocharger pressure is deviated 40 kPa (300 mmHg, 11.8 in.Hg) or more from the simulated target pressure for 0.5 seconds

  • Open or short in VN turbo control circuit

  • Turbocharger

  • Turbocharger actuator

  • EGR valve assembly

  • ECM

WIRING DIAGRAM

Refer to DTC P0045 Click here.

INSPECTION PROCEDURE

Note

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

PROCEDURE


  1. CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC P0234, P0299 AND/OR P1251)


    1. Replace the normal DLC3 cable (12 V specification) for the intelligent tester with the 24 V DLC3 cable.

      Note

      Be sure to use the 24 V DLC3 cable when connecting the intelligent tester to the DLC3. Using the normal DLC3 cable (12 V specification) will cause damage to the tester.

    2. Connect the intelligent tester to the DLC3.

    3. Turn the ignition switch to the ON position and turn the tester ON.

    4. Enter the following menus: Powertrain / Engine and ECT / DTC.

    5. Read the DTCs.

      Result
      Display (DTC Output) Proceed to
      P0234, P0299 and/or P1251 A
      P0234, P0299 and/or P1251 and other DTCs B

    B

    GO TO DTC CHART

    A

  2. CHECK HARNESS AND CONNECTOR (TURBOCHARGER ACTUATOR - ECM)


    1. A01CGQ1E03

      Disconnect the ECM connector.

    2. Disconnect the turbocharger actuator connector.

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

      Standard resistance
      Check for open
      Tester Connection Condition Specified Condition
      E23-29 (VNTI) - T8-5 (PWM OUT) Always Below 1 Ω
      E23-21 (VNTO) - T8-2 (PWM IN) Always Below 1 Ω
      Check for short
      Tester Connection Condition Specified Condition
      E23-29 (VNTI) or T8-5 (PWM OUT) - Body ground Always 10 kΩ or higher
      E23-21 (VNTO) or T8-2 (PWM IN) - Body ground Always 10 kΩ or higher

    4. Reconnect the turbocharger actuator connector.

    5. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (TURBOCHARGER ACTUATOR - ECM)

    OK

  3. CHECK INTAKE AND EXHAUST SYSTEM


    1. Check the intake and exhaust systems modifications.

      OK
      No modifications.

    NG

    REPAIR OR REPLACE INTAKE AND EXHAUST SYSTEM

    OK

  4. CHECK CONNECTION OF VACUUM HOSE


    1. Check the vacuum hoses of turbocharger system connections.


    NG

    REPAIR OR REPLACE VACUUM HOSE

    OK

  5. INSPECT TURBOCHARGER SUB-ASSEMBLY


    1. Check the turbocharger sub-assembly Click here.


    NG

    REPLACE TURBOCHARGER SUB-ASSEMBLY

    OK

  6. INSPECT EGR VALVE ASSEMBLY


    1. Check the EGR valve assembly Click here.


    NG

    REPLACE EGR VALVE ASSEMBLY

    OK

  7. INSPECT MASS AIR FLOW METER


    1. Check the mass air flow meter Click here.


    NG

    REPLACE MASS AIR FLOW METER

    OK

    REPLACE ECM