There was a good This American Life episode recently [1] that walked through a few different alternatives for how VW could respond to this whole scandal. The host solicited feedback from 3 different marketing firms:

One firm, run by the guy who saved Jack In The Box with the ubiquitous sphere-head Jack commercials after an E. Coli outbreak killed 4 kids, said that VW should run an ad of a new executive blowing up the boardroom to symbolize changing the old guard.

Another firm suggested they crowdsource answers to how they can fix the problem/make it up to the public.

The last firm said they should just shut up and not draw attention to themselves. They're not in a good position to say anything right now, and they should just let the collective public forget about it and move onto the next scandal.

I'm assuming the third options is what VW's retainer-ed marketing firm has opted for.

[1] http://www.thisamericanlife.org/radio-archives/episode/569/p...