Home › Jaguar › 2017 › XF S, AWD › Repair and Diagnosis (Single Page) › Quick Lookups › DTC Index › Diagnostic Trouble Code Index DTC: TELEMATIC Control Module (TCU) -- XF/X260 › Diagnostic Trouble Code Index DTC: Telematic Control Module (TCU) › Description And Operation › Telematics Control Module (TCU) › DTC U2109-09: Back-up Battery - Component failures › Possible Causes