This seems to be a common problem on the Voyager. The quick fix is to open the fuse box (under the bonnet) and lift out the fuse marked IOD, count to 5 then put it back in. All should now be working if it is the common problem.
Then pester the dealer into upgrading the software on the body computer to fix the problem properly.
If this doesn't fix it then there are other issues.
UK 2005 Voyager Lx Owner, November 2011