2020 Volkswagen Passat

2020 Volkswagen Passat SE 2.0L VIN: [XXX] Complaint Summary: I am reporting a persistent and unresolved fault involving the secondary air injection system (DTC P0491 – insufficient airflow) that has resulted in repeated, conflicting diagnoses across multiple repair facilities. This raises concerns about a potential systemic defect affecting this vehicle model. Detailed Description: The issue began prior to March 2025 while the vehicle was still under warranty. The vehicle displayed a Check Engine Light associated with diagnostic trouble code P0491 (secondary air injection system insufficient airflow). On April 3, 2025, a repair facility diagnosed the issue as a failed secondary air injection pump and replaced the component. However, the Check Engine Light returned within 24 hours with the exact same fault code, indicating that the repair did not resolve the issue. A second independent diagnostic evaluation was performed later in April 2025. This inspection confirmed that: The secondary air injection pump was functioning correctly Airflow through the system was present Electrical controls and PCM commands were operating properly The fault was attributed instead to a mechanically stuck secondary air injection combination valve Despite this revised diagnosis, the issue has remained unresolved. As of 2026, a dealership evaluation has now attributed the same fault condition to a potential failure within the cylinder head assembly, indicating a significantly more serious underlying condition. Safety Concern: This issue involves the emissions and engine air management system and has resulted in: Persistent Check Engine Light Repeated failure of emissions-related components Conflicting and escalating repair diagnoses across multiple qualified service providers I am requesting that the National Highway Traffic Safety Administration review this issue for potential investigation into a systemic defect. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)