Home >> Jaguar >> 2017 >> XF S, RWD >> Repair and Diagnosis >> General Information >> 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