Diesel particulate filter
Soot particles are collected in the diesel particulate filter and periodically burned away at high temperatures.
During the cleaning period of several minutes:
▷ The engine may temporarily run less 
smoothly.
▷ A somewhat higher engine speed may be 
necessary to achieve the accustomed performance.
▷ Noises and a slight amount of smoke may 
emerge from the exhaust, even for a short 
period after the engine is switched off.
See also:
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Ride & Handling
   One of my main criticisms of the regular X5, which was redesigned for the 
2007 model year, is its regular suspension doesn't offer the balance between 
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Condensation under the parked vehicle
   When using the automatic climate control, condensation 
water develops that exits underneath 
the vehicle.
Therefore, traces of condensed water under the 
vehicle are normal. ...
   
