Citygent

Hi All , I have a 63 plate fabia tdi with 53k mileage, I keep upto speed with servicing etc and never had issues with it until now, both the lights are lit on the dash board and car got me home in emergency mode as owners manual has said it would do . Im stuck on what todo as the im not sure on how to fully fix this as i have had a diagnostic check done, checked for the faults and none were found and the warning lights were cleared on the dashboard, Sadly its happened again 2 days later and the car is in limp home mode, The car upto this point again was driving well again with no issue my local garage has suggested this is a fault on a system that in a reality is not required but is in built into the car so has to stay and the part whilst not cheap can be replaced but stated it may come on again as its more the software than mechanical devices that is driving the fault. Whilst the diagnostics were done they check all the mechanical parts involved and there was no sign of damage/wearing.With having very little knowledge of cars im still trying to understand why the fault is on (when all checks are clearing the fault and the car is running fine when the warnings are not there) and the parts that drive this fault are in good condition. I have used my local garage for over 10 years with several other makes of car and never had any issues and have always been fair with me. Can anyone help me to understand what i cando as i feel i could be throwing good money after bad if this is a situation that will not improve or clear. Thank you.