I made a topic for new owners on the Abarth forum of "Things they may not know" which included the reversing limiter. Here are a few more, which i started, then other added too, most of which you probably know about:
1. Follow me home headlights, remove key from ignition, flash headlight stalk as many times as you want (increases in 30 second intervals up to 210 seconds) and they stay on for that amount of time, even when car is locked
2. Alternatively, there are the parking lights, remove key from ignition and turn the lights on, both front (DRL's) and rear tail lights (including number plate lights) stay on until you turn them off again. Unfortunately you cannot turn just one direction on like on the Panda, it's all or nothing!Don't let your battery run flat though!
3. Auto dimming dash - when the headlights are turned on, the dash lights up too as normal, but if it's not quite dark enough, or the fading sun is directly on the display, the dash illumination goes off and back on as it pleases depending on light conditions.
4. Glove box, yes there is one, awkward bugger to open though! You'll find it!
5. Heated mirrors, if you have the climate control and you press the "de-mist" button, the side view mirrors also heat up to defrost/demist the side mirrors too! Not many people realise this!
6.Hill holder - When on an upward slope, press the brake pedal, when ready to move off, release the brake pedal and the hill holder will hold the car there from about 2 seconds so you don't need to use the handbrake for hill starts!
7. Lane change indicators - lightly push the indicator stalk up or down depending on which direction you want to go, the indicators will flash 3 times, saves the embarrassment of leaving one on if you're on th motorway with the radio full blast!
8. Dimmer - If the dash display back light is a little too harsh at night, go into the menu and reduce it's brightness. There are several things you can do in the menu actually, including turning the passenger airbag off, and turning the DRL's on/off. Worth a look.
Another pointless thing, not really a feature, if you go to lock the car with the remote fob and the hazards flash several times, instead of once, it means one of the doors is not shut properly! Could be the boot. Please note, they flash in the same rhythm as when the ABS locks up!
And also, if you're driving without your seat belt on, you will hear the warning ping, if you indicate whilst the ping is sounding, the indicators do not make a "tick-tock" noise! The ping stops obviously when you put your seat belt on, and/or if you engage reverse.
Another thing that may seem weird at first, if you engage reverse and floor the throttle, the revs will be limited to around 2500 RPM (the A500 is not a fan of reversing!)
The intermittent wiper setting has a longer or shorter delay depending on how fast you are travelling. The rear wiper is the same.
Found out last night that if in Boring mode, I mean normal, the Turbo boost is limited to a max of 0.6 bar.
When the engine is running, none of the buttons on the key fob respond except the unlock one. So you can't lock the car or pop the boot using the key fob when the engine is running.
both windows can be operated after the key has been removed for around 2 mins i think. Until, as you say, the doors are opened!
On a 500c if you hold down the open button on the key remote it opens the roof
Well one is that if you accidentally leave the interior light on, it turns itself off after a while to prevent battery drainage. Nothing special here, i'm sure most cars do this, but saves panicky moments!
As regards to the "lane change" indicators, as we all know, touch it lightly and it flashes 3 times, but if you flick it lightly twice in a row, it flashes 4 times, in case you're performing a slow lane change (what are lanes anyway?)
Hope this helps