If a 2021 Land Rover owner reports intermittent battery drain and the dealer finds B1D9F11 in the BPM event log, the fix is not replacing the battery but reflashing the DDM via JLR’s PATHFINDER 2.0, then performing a LIN bus initialization routine.
Modern Land Rovers and Jaguars are highly sensitive to battery health. A voltage lower than 12.2V can trigger multiple false communication codes in various modules. land rover b1d9f11 2021