Taken from pages 128 & 129 of the Handbook.
Diesel Particulate Filter....
The diesel particle filter system filters harmful soot particles out of the exhaust gases. The system includes a self-cleaning function that runs automatically during driving.
The filter is cleaned by burning off the soot particles at high temperature. This process takes place automatically under set driving conditions and may take up to 25 minutes.
Fuel consumption may be higher during this period. The emission of smells and smoke during this process is normal.
Under certain driving conditions, e.g. short distances, the system cannot clean itself automatically.
If the filter requires cleaning and previous driving conditions did not enable automatic cleaning, control indicator ! flashes. Continue driving, keeping engine speed above 2000 revolutions per minute. Shift down if necessary. Diesel particle filter cleaning is then started.
Stopping the journey or switching off the engine during cleaning is not recommended.
Caution:- If the cleaning process is interrupted more than once, there is a great risk of provoking severe engine damage.
Cleaning takes place quickest at high engine speeds and loads.
The control indicator ! extinguishes as soon as the self-cleaning
operation is complete.