NHTSA complaint #11710289

Owner complaint summary

I am reporting a potential safety-related defect involving the high-voltage battery system and associated diagnostic software in a 2023 Volkswagen ID.4 Pro S AWD. The vehicle has experienced abnormal battery behavior, including accelerated degradation and confirmed system faults affecting battery management, charging, and vehicle communication. An independent EV diagnostic test shows the high-voltage battery at approximately 91% state of health, representing about 9% degradation in under two years of normal use. The testing facility stated this rate of degradation is abnormal for the vehicle’s age, where typical expectations would be significantly lower. In addition, vehicle diagnostics show confirmed and recurring fault codes involving critical systems, including the CAN Gateway (inter-module communication), the high-voltage battery charger/battery management interface, and the emergency call and communication module. These faults are repeatedly logged as “confirmed” and “test failed since last DTC clear,” indicating persistent system-level issues rather than intermittent events. These systems are responsible for battery condition reporting, charging control, communication between vehicle control modules, and safety/telemetry functions. Limitations or failures in these systems raise concerns that battery condition and integrity may not be accurately detected or reported to the driver. Volkswagen dealerships have declined to perform the definitive manufacturer-certified battery capacity test, stating it will not be authorized unless battery capacity is already below warranty thresholds. As a result, more accurate and intrusive testing is unavailable due to manufacturer policy rather than lack of concern. I am also aware of an independent investigation released in January 2026 documenting production-related battery cell defects in Volkswagen Group MEB vehicles from model years 2021–2023, involving increased battery self-discharge and diagnostic measures that may