I doubt this is going to be an issue. Unless you've got duplicate content all over the place, it doesn't lead to any sort of penalty. Google just determines which page to treat as canonical (or you use rel-canonical to indicate your own preference) and they basically just ignore the non-canonical pages.
But assuming each of the dealerships sells a different make, there's no reason the About Us pages have to be identical. Each dealership's page can have information about how long it's been in business, the service department's expertise in working with that particular kind of vehicle, etc.
The Contact Us pages will each have unique addresses and phone numbers, and I imagine the rest of it will be a form. Nothing to worry about there. And you might also consider having a single contact form on a site representing all of the dealerships (if there is one). That way, if a given customer is on the Honda site and goes to the contact form, they'll have the option of requesting information from the other dealerships too. Maybe seeing the option of getting information about not just Hondas, but also Subarus and Jaguars (lots of people who shop for Hondas end up buying Jags, right?) would be good for business.
In other words, I think duplicate content, in this case, should be much less of a concern than thinking of ways to serve your customers as well as you can.