LEMON Manuals: Even more car manuals for everyone
Home >> GMC >> 2018 >> Terrain Denali, FWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 12 (Engine Controls And Fuel - 1.5L (LYX) - Diagnostic Information And Procedures (P0010 - P034B)) >> Diagnostic Information And Procedures >> DTC P0234 Or P0299: Engine Boost >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different variant/trim than selected.
  1. Verify the conditions listed below do not exist:
    • Loose clamps, cracks or other damage in the air intake duct system
    • Collapsed or restricted intake duct system
    • Restricted 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:
      • Q42 turbocharger wastegate solenoid valve
      • Turbocharger wastegate actuator
      • Turbocharger
    • Missing, restricted or leaking exhaust components.
    • Exhaust leak between the turbocharger and the exhaust manifold
    • Restricted or leaking turbocharger oil supply line
    • Loose or incorrect installation of any components
    • If a condition exists 

      Repair or replace the component as necessary.

    • Go to next step: If none of the conditions exist 
  2. Ignition Off, disconnect the Compressor Inlet to Solenoid 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 at least 15% with a scan tool.
    • The pressure does not decrease to 0 kPa (0 inches Hg) 

      Replace the Q42 turbocharger wastegate solenoid valve

    • Go to next step: The pressure decreases to 0 kPa (0 inches Hg) 
  4. Connect the Compressor Inlet to Solenoid hose to the turbocharger.
  5. Disconnect the 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 
    1. Disconnect the wastegate actuator arm from the wastegate.
    2. Verify the wastegate actuator rod moves when applying pressure to the actuator.
      • If the actuator does not move, replace the turbocharger wastegate actuator
      • If the actuator moves, replace the turbocharger
    • Go to next step: If the actuator moves 
    7. NOTE:

    Leave harness connector connected or re-connect it after removing valve.

  7. Ignition Off. Disconnect the Q40 turbocharger bypass solenoid valve ignition On.
  8. Verify the turbocharger bypass valve plunger retracts and extends when commanding the Turbocharger Bypass Solenoid Valve between Active and Inactive with a scan tool.
    • The valve plunger does not retract and extend 

      Replace the Q40 turbocharger bypass solenoid valve

    • Go to next step: The valve plunger retracts and extends 
  9. Verify the conditions listed below do not exist with the turbocharger assembly. Refer to Turbocharger Cleaning and Inspection
    • Cracked, damaged or worn turbine blades
    • Restricted wastegate, turbine, ports or passages
    • Foreign material
    • A condition exists 

      Repair or replace the turbocharger as necessary

    • Go to next step: None of the conditions exist 
  10. Replace the turbocharger.
scientia non olet · About LEMON Manuals