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

P0234
DTC Detection Drive Pattern DTC Detection Condition Trouble Area
Engine coolant temperature is 40°C (104°F) or higher and engine speed is 800 rpm or higher Actual turbocharger pressure deviates 100 kPa (750 mmHg, 29.5 in.Hg) or more from the simulated target pressure for 60 seconds 2 times (1 trip detection logic).

  • Open or short in VN turbo control circuit

  • Turbocharger sub-assembly

  • Turbocharger actuator (built into turbocharger sub-assembly)

  • EGR valve assembly

  • Mass air flow meter sub-assembly

  • Manifold absolute pressure sensor

  • Vacuum hose

  • Exhaust system is clogged

  • ECM
P0299
DTC Detection Drive Pattern DTC Detection Condition Trouble Area
Engine coolant temperature is 40°C (104°F) or higher and engine speed is 800 rpm or higher Actual turbocharger pressure deviates -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 40 seconds 2 times (1 trip detection logic).

  • Open or short in VN turbo control circuit

  • Turbocharger sub-assembly

  • Turbocharger actuator (built into turbocharger sub-assembly)

  • EGR valve assembly

  • Mass air flow meter sub-assembly

  • Manifold absolute pressure sensor

  • Exhaust system and intake system are modified or clogged

  • ECM
P1251
DTC Detection Drive Pattern DTC Detection Condition Trouble Area
Engine speed is 800 rpm or higher Actual turbocharger pressure deviates 40 kPa (300 mmHg, 11.8 in.Hg) or more from the simulated target pressure for 0.5 seconds (1 trip detection logic).

  • Open or short in VN turbo control circuit

  • Turbocharger sub-assembly

  • Turbocharger actuator (built into turbocharger sub-assembly)

  • 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 ON and turn the tester on.

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

    5. Read DTCs.

      Result
      Result Proceed to
      DTC P0234, P0299 and/or P1251 are output A
      DTC P0234, P0299 and/or P1251 and other DTCs are output B

    B

    GO TO DTC CHART Click here

    A

  2. CHECK INTAKE AND EXHAUST SYSTEM


    1. Check the intake and exhaust systems for modifications.

      OK
      No modifications.

    2. Check that the intake and exhaust systems are not clogged.

      OK
      Not clogged.

    NG

    REPAIR OR REPLACE INTAKE AND EXHAUST SYSTEM

    OK

  3. CHECK CONNECTION OF VACUUM HOSE


    1. Check the vacuum hoses of the manifold absolute pressure sensor connections.


    NG

    REPAIR OR REPLACE VACUUM HOSE

    OK

  4. INSPECT TURBOCHARGER SUB-ASSEMBLY


    1. Inspect the turbocharger sub-assembly Click here.


    NG

    REPLACE TURBOCHARGER SUB-ASSEMBLY Click here

    OK

  5. INSPECT EGR VALVE ASSEMBLY


    1. Inspect the EGR valve assembly Click here.


    NG

    REPLACE EGR VALVE ASSEMBLY Click here

    OK

  6. INSPECT MASS AIR FLOW METER SUB-ASSEMBLY


    1. Check the mass air flow meter sub-assembly Click here.


    NG

    REPLACE MASS AIR FLOW METER SUB-ASSEMBLY Click here

    OK

    REPLACE ECM Click here