If this doesn't work, disconnect your neg. battery cable for 20 minutes. This will re-set the parameters in the drive-by-wire... Unfortunately it will delete your pre-set radio stations, clock etc. as well...
While I was running down the problem with my air re-circulation flapper door, I had the radio out of the car for several days. I was very surprised to find the pre-sets were still there when I finally put everything back together!
- Bill