In order to meet European emissions standards applicable to the exhaust system modern diesel vehicles are fitted with a DPF (Diesel Particulate Filter). The DPF captures small soot particles, preventing them from being expelled into the atmosphere. As with any filter it needs emptying periodically and this is done automatically, by burning up the particulates in a process called regeneration.
If your driving profile is unfavorable in other words you only do short urban journeys (often the school run) and you drive mostly around town without the use of carriageways and motorways on a regular basis the DPF on your vehicle can become blocked. They need high temperatures to regenerate, low mileage stop-start motoring can cause them to block this will be caused a build up of soot and once a fault has been stored in the engine management system and a Check Control message issued the vehicle is unable to regenerate itself naturally, this is when the regeneration process must be forced using specialist diagnostic equipment on an extended road test.
Removing your car's diesel particulate filter (DPF) might be tempting, because the damage caused by a clogged DPF can result in expensive repair bills. An internet search reveals numerous companies advertising DPF removal services, but as well as being bad for the environment this is also illegal, and the Government has moved to tighten up the regulations concerning such practices.
If the following warning lamp is displayed in your car it should NOT be ignored as expensive engine damage can occur. At Turner Automotive we are experts at carrying out successful regeneration cycles using the correct procedures recommended by BMW with the use of our specialist diagnostic equipment and not by adding non-approved cleaning agents to clean or remove the DPF completely. Regeneration will only be confirmed by carrying out an exhaust back pressure test where the pressure within the DPF is checked at 3 different engine speeds and only when it falls well below the specified values can it be considered successful.