Volvo V 40, Owner'S Manual

Page: 309 / 492

08 Starting and driving
08
307
Trailer Stability Assist - TSA
The trailer stability assist TSA (Trailer Stability
Assist) function is to stabilise the car and
trailer combination if it begins to snake.
The TSA function is part of the
DSTC system
(Dynamic Stability and Traction Control), see
Stability and traction control system (DSTC)
(p. 185).
Function
The snaking phenomenon can occur with any
car/trailer combination. Snaking normally
occurs at high speeds. But, there is a risk of it
occurring at lower speeds (70-90 km/h) if the
trailer is overloaded or the load is improperly
distributed, e.g. too far back.
In order for snaking to occur, there must be a
triggering factor, e.g.:
•
Car with trailer subjected to a sudden and
powerful side wind.
•
Car with trailer drives on an uneven road
surface or in a pothole.
•
Sweeping steering wheel movements.
Operation
If snaking has started, it could be difficult or
even impossible to suppress. This makes the
car/trailer combination difficult to control and
there is a risk that you could, for example,
end up in the wrong lane or leave the car-
riageway.
TSA system continually monitors car move-
ments, particularly lateral movements. If
snaking is detected, the front wheels are indi-
vidually braked. This serves to stabilise the
car/trailer combination. This is often enough
to help the driver regain control of the car.
If snaking is not eliminated the first time the
TSA system comes into action, the car/trailer
combination is braked with all wheels and
engine power is reduced. Once snaking has
been gradually suppressed and the car/trailer
combination is once again stable, the TSA
system stops regulating and the driver once
again has full control of the car.
Miscellaneous
The TSA system can engage within the speed
interval 65-160 km/h.
NOTE
TSA function is switched off if the driver
selects
Sport
mode, see Stability and
traction control system (DSTC) (p. 185).
TSA may fail to engage if the driver uses
severe steering wheel movements to try to
rectify the snaking because in such a situa-
tion the TSA system cannot determine
whether it is the trailer or the driver that is
causing the snaking.
The DSTC symbol in the combined
instrument panel flashes when the
TSA system is working.
Related information
•
Stability and traction control system
(DSTC) - symbols and messages (p. 187)
•
Stability and traction control system
(DSTC) - operation (p. 186)