The Blue & Me microphone is a common fault and can be replaced easily under warranty. I've not experienced the knocking on mine though so can't be of any further help!
Hi there, I have only had my Fiat 500 since Jan 5th and cos of the snow hasn't been used. But since using it the past week it has a stupid annoying Knocking noise at the front on the passenger side when going over speed bumps like yourself. Took it to the dealer the other day with concerns that it could be stuctural problems. they took car out and heard it and said the then problem was over inflated tyres and wheel nuts needed tightening! The sound has stopped a bit but can still be heard sometimes. Bit annoying so my answer is to turn up my stereo louder! haha! I will be going to the dealer to mention to them that it maybe steering Rack.
And another problem that has come to light is the Blue and Me handsfree system Microphone aint working properly cos no one can hear me properly! Its a brand new car with all these problems, my last 2 grande Punto sportings never had any problems. think the build quality of the 500 is pretty rubbish and FIAT is definately living up to it's name of "Fix It Again Tomorrow."
I have a 2014 500L Trekking. For months, I had an on-again/off-again hard knock under my drivers floor board. It's as if someone is underneath my car with a metal hammer, pounding my floorboard. Turned out to be the intermittent steering column. I had it replaced today and as soon as I drove a quarter mile from the dealership, my steering went out, and my steering wheel was in a 7/12 position to go forward in a straight line. Every light on my panel lit up. I immediately went back to the dealership and they claimed my steering "jumped the splines". Another hour later and it was "fixed". However the alignment was way off still, so they had to send it to Sears Auto to have it aligned. I drove off the lot and five miles to the bank, where the original knocking started all over again. This will be the third time taking it in for service for the same issue, an issue that could cause serious bodily injury or death and therefore qualifies my car to be considered under the Lemon Law. It's a shame because I love my car but it's not worth dying for.