Bagpuss12

New to BMW’s but not to diesels. Just acquired a 318d that’s clocked over 145k miles however was a company car so FSH and very well looked after. The car is now only used to bob around town and very rarely sees a motorway. The particle filter light has since come on so I went for a 40 mins motorway drive doing a steady 55mph in 5th gear and nothing??? It’s now booked in for a forced regen however I don’t want to have to keep doing that!! How come the motorway drive didn’t do the trick?