DTC U2109-09: Back-up Battery - Component failures: Action

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

Check backup battery for poor connection or not connected
Refer to the electrical circuit diagrams and check the telematic control unit module internal battery circuit for open circuit, high resistance. Repair the wiring harness as necessary
Using the Jaguar Land Rover approved diagnostic equipment, clear the DTCs and perform routine - Test Internal Backup Battery (0x040C). If the fault persists, install a new telematic control unit module internal battery. Using the Jaguar Land Rover approved diagnostic equipment, reset the non-rechargeable battery power level following the backup battery replacement process