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Home >> Chevrolet >> 2015 >> Cruze LT, Automatic Trans >> Repair and Diagnosis >> External Pages >> Different car >> Section 89 (Engine Controls And Fuel - 1.4L (LUJ LUV) - DTC P0010 To DTC P0246) >> Diagnostic Information and Procedures >> DTC P0234 or P0299: Engine Overboost >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2015 Chevrolet Trax and 2015 Buick Encore. However, it is still accessible from the selected car via links, so may be relevant.

P0234 

  1. Ignition Off.
  2. Verify the conditions listed below do not exist:
    • Restricted, blocked or incorrect routing of hoses going to the components listed below:
      • Turbocharger
      • Turbocharger wastegate solenoid valve
      • Turbocharger wastegate actuator
    • If a condition exists 

      Repair the condition or replace the turbocharger as necessary

    • If none of the conditions exist 
    3. NOTE:

    The hose is attached between the turbocharger inlet and the Q42 Turbocharger Wastegate Solenoid Valve.

  3. Disconnect the turbocharger wastegate solenoid valve hose at the turbocharger and apply 51 kPa (15 inches Hg) of vacuum to the hose with the GE 23738-A  . Ignition On.
  4. Verify the pressure decreases to 0 kPa (0 inches Hg) when commanding the Turbocharger Wastegate Solenoid Valve to 15 % with a scan tool.
    • If the pressure does not decrease to 0 kPa (0 inches Hg) 

      Test or replace the Q42 Turbocharger Wastegate Solenoid Valve

    • If the pressure decreases to 0 kPa (0 inches Hg) 
  5. Connect the turbocharger wastegate solenoid valve hose to the turbocharger.
  6. Disconnect the wastegate solenoid valve hose from the turbocharger wastegate actuator and connect the exhaust/pressure port of the GE 23738-A  , or a suitable hand pressure pump, to the actuator.
  7. Remove the retaining clip and disconnect the wastegate actuator rod from the wastegate lever.
  8. Verify the wastegate actuator rod moves when applying pressure to the actuator.
    • If the actuator does not move 

      Replace the turbocharger

    • If the actuator moves 
  9. Verify the conditions listed below do not exist with the turbocharger assembly. Refer to Turbocharger Cleaning and Inspection
    • Restricted or damaged wastegate poppet valve.
    • Foreign material.
    • Excessive coking.
    • If a condition exists 

      Repair the condition or replace the turbocharger as necessary

    • If none of the conditions exist 
  10. Replace the turbocharger

P0299 

  1. Verify the conditions listed below do not exist:
    • Loose clamps, cracks or other damage in the air intake duct system
    • Collapsed intake duct system
    • Debris or restrictions in the intake duct system, including the air cleaner dirty side
    • Restricted or aftermarket air filter
    • Any air flow restriction
    • Any air leak between the turbocharger and the throttle body, including the charge air cooler assembly
    • Splits, kinks or improper connections at the vacuum hoses
    • Any vacuum leak
    • Restricted, leaking or incorrect routing of hoses going to the components listed below:
      • Turbocharger wastegate solenoid valve
      • Turbocharger bypass solenoid valve
      • Intake manifold and turbocharger vacuum reservoir on the bottom of intake manifold
      • Turbocharger
      • Turbocharger wastegate actuator
      • Turbocharger bypass valve
    • Exhaust leak between the turbocharger and the exhaust manifold
    • Loose or incorrect installation of any components
    • Evidence of oil contamination in the wastegate solenoid valve and/or vacuum hoses

      Refer to Intake Manifold Cleaning and Inspection for inspection of the positive crankcase ventilation (PCV) diaphragm and check valve.

    • Increased or excessive crankcase pressure

      Refer to Engine Compression Test for additional diagnosis.

      • If a condition exists 

        Repair or replace the affected component as necessary.

      • If none of the conditions exist 
    2. NOTE:

    The hose is attached between the turbocharger inlet and the Q42 Turbocharger Wastegate Solenoid Valve.

  2. Ignition Off, disconnect the turbocharger wastegate solenoid valve hose at the turbocharger and apply 51 kPa (15 inches Hg) of vacuum to the hose with the GE 23738-A  . Ignition On.
  3. Verify the pressure decreases to 0 kPa (0 inches Hg) when commanding the Turbocharger Wastegate Solenoid Valve to 15 % with a scan tool.
    • If the pressure does not decrease to 0 kPa (0 inches Hg) 

      Test or replace the Q42 Turbocharger Wastegate Solenoid Valve

    • If the pressure decreases to 0 kPa (0 inches Hg) 
  4. Connect the turbocharger wastegate solenoid valve hose to the turbocharger.
  5. Disconnect the wastegate solenoid valve hose from the turbocharger wastegate actuator and connect the exhaust/pressure port of the GE 23738-A  , or a suitable hand pressure pump, to the actuator.
  6. Verify the wastegate actuator rod moves when applying pressure to the actuator.
    • If the actuator does not move 

      Replace the turbocharger

    • If the actuator moves 
  7. Disconnect the Q40 Turbocharger Bypass Solenoid Valve vacuum hose at the turbocharger bypass valve on the turbocharger.
  8. Connect the GE 23738-A  to the hose.
  9. Idle engine for at least 15 s.
  10. Engine Off, ignition On.
  11. Verify the vacuum decreases to 0 kPa (0 inches Hg) when engine is turned Off and increases to greater than 45 kPa (13 inches Hg) for at least 5 s when the Turbocharger Bypass Solenoid Valve is commanded On with a scan tool.
    • If not within the specified range  
      NOTE:

      The vacuum reservoir (tank) is integral to intake manifold and is located underneath the manifold.

    1. Ignition Off, disconnect the vacuum hose from the turbocharger vacuum reservoir.
    2. Connect the GE 23738-A  to the vacuum reservoir and apply 34 kPa (10 inches Hg) of vacuum.
    3. Verify the reservoir holds vacuum for at least 10 s.
      • If the vacuum is not held for at least 10 s

        Replace the intake manifold

      • If the vacuum is held for at least 10 s
    4. Reconnect the vacuum hose to the turbocharger vacuum reservoir.
    5. Disconnect the vacuum hose that runs between the intake manifold and the Q40 Turbocharger Bypass Solenoid Valve hose at the intake manifold and connect the GE 23738-A  to the hose.
      6. NOTE:

      Allow engine idle to stabilize before continuing.

    6. Engine idling, verify the vacuum is greater than 45 kPa (13 inches Hg).
      • If 45 kPa (13 inches Hg) or less

        Replace the intake manifold

      • If greater than 45 kPa (13 inches Hg)
    7. Connect the GE 23738-A  to the output port on the Q40 Turbocharger Bypass Solenoid Valve.
      8. NOTE:

      The Q40 Turbocharger Bypass Solenoid Valve is supplied with vacuum from both the intake manifold and the vacuum reservoir at idle. The vacuum supply hose from the intake manifold must be disconnected before proceeding, to allow vacuum to bleed off when changing command states.

    8. Engine idling, command the Turbocharger Bypass Solenoid Valve On and Off with a scan tool.
    9. Verify the vacuum toggles between 0 kPa (0 inches Hg) to greater than 45 kPa (13 inches Hg).
      • If not within the specified range

        Test or replace the Q40 Turbocharger Bypass Solenoid Valve

      • If within the specified range

        Replace the vacuum line between the Q40 Turbocharger Bypass Solenoid Valve and the turbocharger bypass valve.

    • If within the specified range 
  12. Verify the conditions listed below do not exist.
    • Insufficient preload between the wastegate lever and actuator rod.
    • Cracked or damaged turbine blades.
    • Worn turbine blades due to contact with housing.
      • NOTE:

      Excessive oil is not necessarily an indication of turbocharger failure.

    • Oil intrusion in turbocharger, hoses or charge air cooler. Refer to Turbocharger Cleaning and Inspection
    • Restricted wastegate, turbine, ports or passages.
    • Foreign material.
    • Damaged or restricted bypass valve assembly.
    • Missing, restricted or leaking exhaust components. Refer to Symptoms - Engine Exhaust
    • Restricted turbocharger oil supply line
    • Restricted charge air cooler
    • If a condition exists 

      Repair or replace the turbocharger as necessary

    • If none of the conditions exist 
  13. Replace the turbocharger.
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