NHTSA complaint #11741109

Owner complaint summary

Component/System: 48V Mild Hybrid Electric Vehicle (MHEV) system including the DC/DC Converter (subject of active recall D126), Battery Energy Control Module (BECM), Telematics Control Unit (TCU), Battery Charge Control Module (BCCM), and Vehicle Immobilizer Module (VIM). All components are available for inspection upon request. What happened: My 2021 Range Rover Sport HSE MHEV (VIN: [XXX] ) experienced a complete no-start condition after sitting for approximately one week. Prior to towing the vehicle to Hendrick Jaguar Land Rover Charlotte, I performed a live data diagnostic using a Land Rover specific iCarsoft LR V3 diagnostic tool which confirmed the 48V hybrid battery at 17.86% state of charge critically below the minimum threshold required to authorize a start sequence. The TCU, BCCM, and VIM all showed not fitted simultaneously a known cascade effect of a critically depleted 48V MHEV system. Recall D126 for DC/DC Converter failure was confirmed on my vehicle. The DC/DC converter manages power transfer between the 48V and 12V systems. Its failure directly caused the 48V battery depletion and subsequent cascade module failures. Safety risk: The vehicle became completely immobile with no warning. The immobilizer went offline preventing the vehicle from starting, stranding the occupant in a parking lot. A vehicle that shuts down without warning and cannot be restarted poses a serious safety risk to the driver and other road users. Additionally the DC/DC converter failure affecting the MHEV system represents a risk of sudden loss of hybrid assist during driving. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)