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Home >> GMC >> 2018 >> Acadia Denali, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 277 (Engine Controls And Fuel - 3.6L (LGX LF4) - DTC P0010 To DTC P0119 (LF4)) >> Diagnostic Information and Procedures >> DTC P00C4 or P2261: Turbocharger Bypass Valve Stuck Bank >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2017 Cadillac ATS. However, it is still accessible from the selected car via links, so may be relevant.
  1. Verify the conditions listed below do not exist:
    • Vacuum leaks
    • Vacuum line restrictions
    • Improper routing or connections to the vacuum hoses for the Q40 Bypass Solenoid Valves, bypass valves, Q42 Turbocharger Wastegate solenoid valves, wastegate valve actuators, vacuum pump and the vacuum tank.
    • If a condition exists 

      Repair or replace the component as necessary.

    • If none of the conditions exist 
  2. Ignition Off, disconnect the vacuum supply hose at the turbocharger vacuum pump.
  3. Connect the GE 23738-A  to the pump outlet.
  4. NOTE:

    To determine the absolute vacuum value, subtract the vacuum gauge reading from the barometric pressure.

  5. Engine Idling, verify the absolute vacuum value is less than or equal to 15 kPa (4.4 inches Hg).
    • If not within the specified range 

      Repair or replace the vacuum pump.

    • If within the specified range 
  6. Ignition Off, disconnect all vacuum hoses at the turbocharger vacuum tank and cap or plug the valve outlet ports.
  7. Connect the GE 23738-A  to the vacuum tank inlet port and apply 5 kPa (1.5 inches Hg) of vacuum.
  8. Verify the tank holds vacuum for at least 10 s.
    • If the vacuum is not held for at least 10 s 

      Replace the vacuum tank.

    • If the vacuum is held for at least 10 s 
  9. Connect the vacuum hoses to the tank.
  10. Disconnect the appropriate Q40 Turbocharger Bypass Solenoid Valve output to bypass valve input vacuum hose at the bypass valve and connect the GE 23738-A  to the hose.
  11. Engine idling.
  12. NOTE:

    To determine the absolute vacuum value, subtract the vacuum gauge reading from the barometric pressure.

  13. Verify the absolute vacuum value toggles between 0 kPa (0 inches Hg) to less than or equal to 15 kPa (4.4 inches Hg), when commanding the Turbocharger Bypass Solenoid Valve between Active and Inactive with a scan tool.
    • If not within the specified range 

      Replace the Q40 Turbocharger Bypass Solenoid Valve.

    • If within the specified range 
  14. Connect any hoses that were disconnected during previous steps.
  15. Verify the conditions listed below do not exist with the turbocharger bypass valve assembly:
    • Damage
    • Leaks
    • Restrictions
    • If a condition exists 

      Repair or replace the turbocharger bypass valve as necessary.

    • If none of the conditions exist 
  16. Replace the B111B Turbocharger Boost/Intake Air Temperature Sensor.