Home >> Jaguar >> 2018 >> F-Pace S >> Repair and Diagnosis >> Quick Lookups >> DTC Index >> Diagnostic Trouble Code Index DTC: Telematics Control Module (TCU) - F-Pace >> Diagnostic Trouble Code Index DTC: Telematics Control Module (TCU) >> Description And Operation >> Telematics Control Module (TCU) >> DTC U2109-91: Back-up Battery - Parametric >> Possible Causes