Gen III package IV rattle from undercarriage near the left front wheel. Sounds like a few coins in the bottom of a tin can. Every time I hit a series of those little square plastic looking markers that appear mostly where you have double yellow lines in the roadway. I told the dealer yesterday that it sounds like a loose clip.....the clip that holds the brake disc pads in place. Dealer said they couldn't find it because they couldn't reproduce the noise. Anyone else had this admittedly minor ailment?
Hope you got it fixed. Did you ever find out what this was? I have the same issue. Just like coins rattling around.
What you are describing is most assuredly the front caliper rattling. I have complained about this on my Prius since new. It is so bad that you can hear the rattle (snapping) echoing off the buildings. I had it in to 2 different dealers and both turned a blind eye. Toyota knows about this and refuses to address the problem. Interestingly, there is a TSB for this condition on 2010-2011. However, Toyota has determined on the later models, that it is a normal condition and poses no safety concerns. Tell that to a Lexus owner. It’s pure BS.