Check engine light with reduced power with fault codes P300A6D, P300974, P300DFB, or P300DE8 Complaint The...

Bulletin number

LI09_40-N-079144_10_en

Component

Engine

Summary

Check engine light with reduced power with fault codes P300A6D, P300974, P300DFB, or P300DE8 Complaint The check engine light is activated, accompanied by one or more of the following fault codes related to the boost pressure positioner: • P300A6D: The boost pressure is too low. Charge air cooler. • P300A6F: The boost pressure is too low. (High‑pressure turbocharger) • P300A71: The boost pressure is too low. (Low‑pressure turbocharger) • P300974: Component 'Boost pressure positioner' has a malfunction. The boost pressure is too low. • P300DFB: Component 'Boost pressure positioner' has a malfunction. • P300DE8: Boost pressure control A has a malfunction after a cold start. Cause The potential causes for these fault codes are: A. Leak or Blockage in the Intake or Charge Air System: This can prevent proper airflow, affecting boost pressure. B. Insufficient Source Vacuum, Vacuum Leak, or Sticking/Weak Vacuum Component: These issues can prevent the boost pressure positioner from functioning correctly. • For Model Year 2023‑Current vehicles operating at approximately 4,000 ft elevation or above, reduced ambient pressure and/or high brake demand may contribute to reduced available vacuum differential and underboost complaints, even when no discrete vacuum component failure is identified. C. Internal Malfunction of the Boost Pressure Positioner: The component itself may be faulty. D. Internal Defect with the Variable Turbine Geometry (VTG) System Inside the Turbocharger: Issues within the turbocharger can affect boost pressure control.

Owners of these vehicles have filed 9 complaints in the engine category.