“The creator of this fault did not specify a Reason” Exception

After some addtional research, the following modified code worked:

if(!DidItPass)
{    
    InvalidRoutingCodeFault fault = new InvalidRoutingCodeFault("Invalid Routing Code - No Approval Started");    
    throw new FaultException<InvalidRoutingCodeFault>(fault, new FaultReason("Invalid Routing Code - No Approval Started"));
}