It's not clear why your X.XREF_STATUS duplicates: there are dups in TABLE3 table? Or, more likely, there are many references to XREF_STATUS values in related records?
If rows differs for other columns than X.XREF_STATUS, you won't be able to pick one row instead of another to show only unique X.XREF_STATUS values.
A list of unique X.XREF_STATUS values can be obtained with:
select distinct X.XREF_STATUS from TABLE3.XREF_DATA X where x.code=4545645 AND X.VEHICLE_CODE=9999999
This can be joined to other tables to obtain related data, but again if you join with a table containing more than one reference to X.XREF_STATUS this will dup accordingly. You must aggregate other columns (COUNT, SUM, etc.) to avoid dups.