PivotTable.FieldListSortAscending (Excel)

Controls the sort order of fields in the PivotTable Field List. When this property is set to True, the fields are sorted in ascending order. When it is set to False, the fields are sorted in data source order.

Does not apply to PivotTables connected to OLAP data sources.

ActiveCell.PivotTable.FieldListSortAscending = True