Audi A8 2019 Service Training page 75

Pre sense basic
Reversible belt tensioners
If the vehicle has the optional separate rear seats, the rear
outer seats are equipped with reversible seat belt tension-
ers in addition to the front reversible seat belt tensioners.
The functions of the front and rear reversible seat belt
tensioners are identical. The following information there-
fore refers to both the front and rear reversible seat belt
tensioners.
Definition and function of the belt slack reduction system for reversible seat belt tensioners
In certain situations, for example, when wearing a thick
winter jacket, it is possible that after fastening the revers-
ible seat belt, it does not tighten against the body. In this
case, the wind-up force of the automatic seat belt retractor
is less than the force required to compress the thick winter
jacket. The distance which the seat belt can travel until it
fits the front occupants perfectly is termed "belt slack".
Seat belt fitting tightly
(low belt slack)
With Audi pre sense basic, the following actions can be
taken:
› Belt slack reduction.
› Partial tensioning of the electrically reversible seat belt
tensioners.
› Full tensioning of the electrically reversible seat belt
tensioners.
› Closing of the panoramic sunroof.
› Closing of the side windows apart from a residual gapv
› Inflation of the side bolsters in the seats and backrests.
› Display of corrective action by Audi pre sense in the
instrument cluster.
The seat belt is tightened with defined force by the revers-
ible seat belt tensioners under the following conditions:
This enables any existing belt slack to be reduced.
› If the vehicle reaches a speed of about 9.3 mph
(15 km/h) after starting the engine and traveling for-
wards.
› If the vehicle has not reached a speed of 9.3 mph
(15 km/h) about 10 seconds after starting the engine
and traveling forwards.
Seat belt on "thick" clothing
(greater belt slack)
662_079 662_080
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