Porsche Cayenne User Handbook Manual page 70

Preparing for the road ahead.
With a little help from PSM.
70 · Safety and environment | Safety
Porsche Stability Management (PSM).
Porsche Stability Management (PSM) is
an electronic control system that uses a
range of functions – including anti-lock
braking (ABS) – to help stabilise the
vehicle (and trailer, if fitted) in hazardous
road scenarios. Throughout each journey,
sensors monitor the direction, speed,
yaw velocity and lateral acceleration of
the car. Using this information, it is pos-
sible to calculate the actual direction of
travel at any given moment. If the car
begins to oversteer or understeer, PSM
applies selective braking on individual
wheels to restore stability. If necessary,
PSM can also intervene in the engine
management system to temporarily
modify the amount of drive transmitted
to the wheels.
PSM has three additional functions that
help reduce braking distances. If the
throttle pedal is released suddenly, PSM
automatically readies the braking sys-
tem. The pressure in the brake lines
is marginally increased, bringing each
of the pads into light contact with the
corresponding disc. If the driver goes on
to apply the brakes, the calipers respond
more quickly and the braking distance is
reduced.
In an emergency stop – i.e. when the
pressure on the brake pedal exceeds
a certain threshold – the brake assist
function uses the PSM hydraulics to
apply maximum braking force at all four
wheels.