Diesel Particulate Filter; Driving Through Water - BMW 323i Owner's Manual

Diesel particulate filter*

The diesel particulate filter collects soot parti-
cles and burns them periodically at high tem-
peratures. This cleaning process takes several
minutes. During cleaning, you may notice that
the engine temporarily runs less smoothly and
that a somewhat higher engine speed is neces-
sary to achieve the accustomed performance.
Also, noises may be heard and a slight amount
of smoke may emerge from the exhaust, even
for a short period after the engine is switched
off.
Hydroplaning
When driving on wet or slushy roads,
reduce road speed. If you do not, a wedge
of water can form between tires and road sur-
face. This situation, known as hydroplaning,
means that the tire can completely lose contact
with the road surface, so that neither the car can
be steered nor the brake be properly
The risk of hydroplaning increases with declin-
ing tread depth on the tires, refer also to Mini-
mum tread depth on page 136.

Driving through water

Drive through water on the road only if it is
not deeper than 1 ft/30 cm, and then only
at walking speed at the most. Otherwise, the
vehicle's engine, the electrical systems and the
transmission may be damaged.<
Use the parking brake on inclines
On inclines, do not hold the vehicle for a
lengthy period using the clutch; use the
parking brake instead. Otherwise, greater
clutch wear will result.<
For more information about the drive-off assis-
tant, refer to page 74.
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Braking safely
Your BMW is equipped with ABS as a standard
feature. Applying the brakes fully is the most
effective way of braking in situations in which
this is necessary. Since the vehicle maintains
steering responsiveness, you can still avoid
possible obstacles with a minimum of steering
effort.
Pulsation of the brake pedal, combined with
sounds from the hydraulic circuits, indicate that
ABS is in its active mode.
Driving in wet conditions
When roads are wet or there is heavy rain,
briefly exert gentle pressure on the brake pedal
every few miles. Monitor traffic conditions to
ensure that this maneuver does not endanger
other road users. The heat generated in this
process helps dry the pads and rotors to ensure
that full braking efficiency will then be available
applied.<
when you need it.
Hills
To prevent overheating and the resulting
reduced efficiency of the brake system,
drive long or steep downhill gradients in the
gear in which the least braking is required. Even
light but consistent brake pressure can lead to
high temperatures, brake wear and possibly
even brake
You can increase the engine's braking effect by
shifting down, all the way to first gear if neces-
sary. This strategy helps you avoid placing
excessive loads on the brake system. Down-
shifting in manual mode of the automatic trans-
mission, refer to page 50.
Never drive with the clutch held down,
with the transmission in neutral or with
the engine switched off; otherwise, engine
braking action will not be present or there will be
no power assistance to the brakes or steering.
Never allow floor mats, carpets or any other
objects to protrude into the area around the
pedals; otherwise, pedal function could be
impaired.<
failure.<