Fiat 500 2018 Owner's Manual page 104

102 SAFETY
A feature of the TCS system, Brake Limited Differential
(BLD), functions similar to a limited slip differential and
controls the wheel spin across a driven axle. If one wheel
on a driven axle is spinning faster than the other, the
system will apply the brake of the spinning wheel. This
will allow more engine torque to be applied to the wheel
that is not spinning. This feature remains active even if TCS
and ESC are in the Partial Off mode. Refer to "Electronic
Stability Control (ESC)" in this section for further informa-
tion.
Hill Start Assist (HSA)
The HSA system is designed to assist the driver when
starting a vehicle from a stop on a hill. HSA will maintain
the level of brake pressure the driver applied for a short
period of time after the driver takes his foot off 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 the 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 2.5% (manual transmission) or 7%
grade or greater (automatic transmission) hill.
• Gear selection matches vehicle uphill direction (i.e.,
vehicle in NEUTRAL (manual transmission), vehicle
facing uphill is in forward gear; vehicle backing uphill is
in REVERSE gear).
WARNING!
There may be situations on minor hills 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.