There is a good chance that it takes a standard size socket rather than a metric socket, it was like this on my Toyota Celica. 17mm
Its a 28mm socket.
I changed my oil today, the drain plug is 15 mm.
It is 25 mm socket.
If it's the "oil" drain plug, the size wrench is, better yet use a socket wrench=13mm.
If the drain plug is original equipment, it takes a 17mm wrench or socket.
it takes 1" socket on it good luck on it
It's in metric: 14mm.
17mm worked for our 2009 this am Feb 14,2009