So about 6/7 months into ownership I've got a really weird issue with my A3 8V. About 30-40mins into driving, my stop/start and say Automatic Stop/Start System Fault: Function Not Available, my heater fan speed gets reduced and doesn't work at full fan speed and the engine revs at 1100rpm when idle. I've only started to experience these faults when the car was sat for 6 days and it popped up with a message saying Low Battery: Battery will charge during drive but since then I've covered 400 miles which has been motorway mileage. It's got a 12v cigarette lighter splitter which has a dashcam and footwell lights connected, I don't know if that could be causing an issue but any help or advice would be appreciated.