thanks for the info re key fobs ,have had a 2017 green fabia and now a green scala , both my keyfobs have gone through the same scenario , and as an electronic tech for many many years have some knowledge and found both keyfobs exhibiting indentical low battery warnings , what i found upon close scrutiny two marks on the underside of the battery case where the finger contacts connect very minimal signs of increased resistance which on clean up has resulted in ongoing reliability, if the fob failed away from home even removing the battery and repositioning it could achieve a result especially if holding the fob to the start button failed , hope this clarifies my previous post ps this is only my second post so i'm still learning