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

NOTE: This DTC will cause the warning "SOS limited functionality" to be displayed on the instrument cluster

Check backup battery for poor connection or not connected
Refer to the appropriate system wiring diagrams and check the telematics control module internal battery circuit for open circuit, high resistance
Using the Jaguar Landrover 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