Interesting tidbit
Unfortunately the Fiesta is 2009 car (or maybe luckily as I would find quite annoying to have the car bugger me with such a show every time I got low on fuel).
Many road cars in LFS are a bit older than that. In that period it was still common not to include things (including lights) that are regarded common as of now - some cheap models didn't even have an e-brake light, and some brands simply insisted on not including a reserve light until much later.
An audio alert would be quite annoying in pickup racing anyway, whenever you load so little fuel that you would start off the race already in reserve.
E.g. the XFG on the classic 5 lapper on BL1, would take 6-7% of its 45L tank, for a grand total of 2.7L.