I would get it checked I don't think the pump should be seeing 17volts!! Damo V for example wired a direct supply from his battery to the pump (including relay & fuse) to make sure he had a reliable 12 volts..... I think my pump is getting about 10-11 volts (a bit low ) - so I am thinking of doing the same as Damo..... Yours is a bit high though...