don't bother just every week or so get the engine up to normal operating temperature then give it some beans in the lower gears for a bit on a quiet road. You might actually quite enjoy the drive too.

I have a BMW 530D - the car has done slightly over 100,000 miles. The particulate filter light came on. Not knowing anything about this I researched the subject and asked a mechanic friend.

Basically it catches the soot produced by your engine and colder temperatures and burns it off at higher temperatures when you are crusing down the road at 50 mph.

The cost of a replacement filter on the BMW is £1500 before fitting! I ws somewhat horrified.

Long story short, my mechanic friend took the filter apart and washed in in a petrol solution. Loads of black muck came out of it. This turned off the light and worked for a month. Light on, so I bought the filter product JML particulate filter cleaner. After a 50 mile trip down the motorway this also worked and turned off the light. A month later the light was back on. Finally using the grey matter in my head I deduced that the soot was created at lower temperatures and decided to try one last thing.

I used JML cleaner again and this time I only used the premium diesel sold by Shell. More expensive, but you recover the costs in my case I get about 50 miles more out of a tank.

No more lights on after 6 months - still fine. I believe a combination of factors caused my problem. The age and mileage of the filter and also supermarket diesel.

Hope this helps anyone with filter issues.