2009 JEEP WRANGLER UNLIMITED Owners Manual

HSA on Automatic Transmission Vehicles
The system will work in REVERSE, and all forward gears
on vehicles equipped with an automatic transmission.
The system will not activate if the vehicle is placed in
NEUTRAL.
HSA on Manual Transmission Vehicles
The system will work in REVERSE, forward gears, and
NEUTRAL on manual transmission equipped vehicles.
The system does not recognize NEUTRAL on manual
vehicles, thus it will hold the vehicle on an incline for a
short period while in NEUTRAL, regardless of clutch
position. To prevent this, do not attempt to roll down a
hill simply by putting the transmission in NEUTRAL and
letting gravity act on the vehicle, as the HSA will prevent
the vehicle from rolling. Instead, use the appropriate gear
for moving in the desired direction.
Towing with HSA
HSA will provide assistance when starting on a grade
when pulling a trailer.

speed of the vehicle. When ERM determines that the rate
of change of the steering wheel angle and vehicle’s speed
are sufficient to potentially cause wheel lift, it applies the
appropriate brake and may reduce engine power to
lessen the chance that wheel lift will occur. ERM will only
intervene during very severe or evasive driving maneu-
vers.
Electronic Roll Mitigation (ERM) can only reduce the
chance of wheel lift occurring during severe or evasive
driving maneuvers. It cannot prevent wheel lift due to
other factors such as road conditions, leaving the road-
way or striking objects or other vehicles.
NOTE:Anytime the ESP system is in the “Full Off”
mode, ERM is disabled. Refer to ESP (Electronic Stability
Program) for a complete explanation of the available ESP
modes.

WARNING!
With the ESP switched off, the enhanced vehicle
stability offered by ESP and ERM are unavailable. In
an emergency evasive maneuver, the ESP and ERM
systems will not engage to assist in maintaining
stability. The “Full Off” ESP mode is intended for
off-road use only.
4L Range (4WD Models)
ESP Off
This is the normal operating mode for ESP in 4L range.
Whenever the vehicle is started in 4L range, or the
transfer case (if equipped) is shifted from 4H range or
NEUTRAL to 4L range, the ESP system will be in this
mode. In 4L range, ESP and TCS, except for the “limited
slip” feature described in the TCS section, are turned off
until the vehicle reaches a speed of 40 mph (48 km/h). At
40 mph (48 km/h), the normal ESP stability functionreturns but TCS remains off. When the vehicle speed
drops below 35 mph (40 km/h), the ESP system shuts off.
The ESP is off at low vehicle speeds in 4L range so that it
will not interfere with off-road driving, but the ESP
function returns to provide the stability feature at speeds
above 40 mph (48 km/h). The “ESP/TCS Indicator
Light” will always be illuminated in 4L range when ESP
is off.
NOTE:
The “ESP OFF” message will display and the
audible chime will sound when the shift lever is placed in
the PARK position from any position other than PARK,
and then moved out of the PARK position. This will
occur even if the message was previously cleared.
326 STARTING AND OPERATING