How did you accomplish this?
Maybe the fact that you did this hack affected the operation of the GPS system??
Why don't you bring the car into your dealer and have them check out this problem?
How long has this Wal-Mart been at this location? Reason being, if the DVD Nav disc was produced before this retailer was located there, it won't be included in the information displayed on your NAV screen.
Naw, the thing can't find streets that have been there for 15 years! Also I did find my WalMart in the data base but I had to dig very deep. When I told the Lexus rep about the WalMart issue seh said, "Mine did the same thing but there's a way to fix that." When I asked how she did it she replied that she doesn't remember since she knows where it is! That tells me that the Lexus rep even gave up on it.
There are two ways around the speed switch. One involves cutting a wire which I won't do. The other uses the touch screen and is well documented on the internet. Only thing is that you have to do it each time you start the car.