i had the same problem with my car.. not so long ago...
my problem was that the connection got disconnected.. so i plug it back in.. which means i had to take out the whole bashboard apart... now if its connected and it works now and then.. it might be getting loose or wire mess up... finally if it doenst work.. even if its connected.. you computer might be mess up.. hopefully it aint.. well hope that i helped.. umm barely.. gettting to know about cars...