DTC U2109-91: Back-up Battery - Parametric: Action

NOTE: Following an emergency call or stolen vehicle tracking alert, a new telematics control module internal battery must be installed before this DTC can be cleared

Using JLR approved diagnostic equipment, clear the DTCs and perform routine - Test Internal Backup Battery (0x040C)
Using JLR approved diagnostic equipment, clear the DTCs and perform routine - Test Internal Backup Battery (0x040C). If the fault persists, install a new telematics control module internal battery. Using JLR approved diagnostic equipment, reset the non rechargeable battery power level following the backup battery replacement process