Jeep 2009 Grand Cherokee, Owner'S Manual, Page: 323 / 521

period of time after the driver takes their foot off of the
brake pedal. If the driver does not apply the throttle
during this short period of time, the system will release
brake pressure and the vehicle will roll down the hill. The
system will release brake pressure in proportion to
amount of throttle applied as the vehicle starts to move in
the intended direction of travel.
HSA Activation Criteria
The following criteria must be met in order for HSA to
activate:
•
Vehicle must be stopped.
•
Vehicle must be on a 8% grade or greater hill.
•
Gear selection matches vehicle uphill direction (i.e.,
vehicle facing uphill is in forward gear; vehicle back-
ing uphill is in REVERSE gear).
HSA will work in REVERSE and all forward gears when
the activation criteria have been met. The system will not
activate if the vehicle is placed in NEUTRAL or PARK.
WARNING!
There may be situations on minor hills (i.e., less than
8%), with a loaded vehicle, or while pulling a trailer,
when the system will not activate and slight rolling
may occur. This could cause a collision with another
vehicle or object. Always remember the driver is
responsible for braking the vehicle.
Towing with HSA
HSA will provide assistance when starting on a grade
when pulling a trailer.
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