Hi. So I am the 2nd owner of my Citroen C5 2002 Petrol HDi Tiptronic, she has just topped 200 000 km on the clock (yes, I have driven the hell outta her - I have a commute of over 100km a day and do a lot of cross-country travel in her). I have had her for a year now and she is the best car I've ever driven. BUT she recently has had an anti-pollution fault pop up. This happened a week ago. I have noticed no difference in power/speed/handling except that last Friday night after work my car cut out on the motorway while travelling at 110Km/h. It just completely died. I felt a thud/jerk and then everything went black. I pulled over, turned off the ignition, waited about a minute and it started again with no issue. I then drove a further 40km home with no issues and have had no further issues since. But the light is still on?! And it is bugging me. What on earth could this be? I have been very naughtily using cheaper fuel in the last few months even though I was advised to use premium (and will do so when I next fill her up!). Could it just be my fuel mix? My car has recently been fully serviced and WOF'd and no one mentioned any issues with her then? I have looked online at other forums and everyone else who has had this fault come up has noticed significant loss of power or had their car continuously cut out - I am having no problems at all with her. I have also checked/charged the battery and it's all working fine. I am stumped! Can anyone shed some light on the matter?