2008 JEEP WRANGLER sensor

Airbag System Components
The airbag system consists of the following:
•Occupant Restraint Control (ORC) Module
•Airbag Warning Light
•Driver Airbag
•Passenger Airbag
•Front Seat-Mounted Side Airbags (If Equipped)
•Steering Wheel and Column
•Instrument Panel
•Interconnecting Wiring
•Knee Impact Bolsters
•Front Acceleration Sensors
•Remote Side Impact Acceleration Sensors (If
Equipped)
•Driver Seat Track Position Sensors
•Driver and Front Passenger Seat Belt Pretensioner
How The Airbag System Works
•
TheOccupant Restraint Control (ORC) Module de-
termines if a frontal or side collision is severe enough
to require the front and/or side airbags to inflate. The
front airbag inflators are designed to provide different
rates of airbag inflation from direction provided by the
ORC.
The ORC also monitors the readiness of the electronic
parts of the system whenever the ignition switch is in
the START or ON positions. These include all of the
items listed above except the knee bolster, the instru-
ment panel, and the steering wheel and column. If the
key is in the LOCK position, in the ACC position, or
not in the ignition, the airbags are not on and will not
inflate.
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ESP (Electronic Stability Program)
This system enhances directional control and stability of
the vehicle under various driving conditions. ESP cor-
rects for over/under steering of the vehicle by applying
the brake of the appropriate wheel to assist in counter-
acting the over/under steer condition. Engine power
may also be reduced to help the vehicle maintain the
desired path.
ESP uses sensors in the vehicle to determine the vehicle
path intended by the driver and compares it to the actual
path of the vehicle. When the actual path does not match
the intended path, ESP applies the brake of the appropri-
ate wheel to assist in counteracting the oversteer or
understeer condition.
•Oversteer - when the vehicle is turning more than
appropriate for the steering wheel position.
•Understeer - when the vehicle is turning less than
appropriate for the steering wheel position.
The ESP/TCS Indicator Light (located in the instrument
cluster), starts to flash as soon as the tires lose traction
and the ESP system becomes active. The ESP/TCS Indi-
cator Light also flashes when TCS is active. If the
ESP/TCS Indicator Light begins to flash during accelera-
tion, ease up on the accelerator and apply as little throttle
as possible. Be sure to adapt your speed and driving to
the prevailing road conditions.
UNDERSTANDING THE FEATURES OF YOUR VEHICLE 109
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Your vehicle has also been equipped with a TPMS
malfunction indicator to indicate when the system is not
operating properly. The TPMS malfunction indicator is
combined with the low tire pressure telltale. When the
system detects a malfunction, the telltale will flash for
approximately one minute and then remain continuously
illuminated. This sequence will continue upon subse-
quent vehicle start-ups as long as the malfunction exists.
When the malfunction indicator is illuminated, the sys-
tem may not be able to detect or signal low tire pressure
as intended. TPMS malfunctions may occur for a variety
of reasons, including the installation of replacement or
alternate tires or wheels on the vehicle that prevent the
TPMS from functioning properly. Always check the
TPMS malfunction telltale after replacing one or more
tires or wheels on your vehicle to ensure that the replace-
ment or alternate tires and wheels allow the TPMS to
continue to function properly.CAUTION!
The TPMS has been optimized for the original
equipment tires and wheels. TPMS pressures and
warning have been established for the tire size
equipped on your vehicle. Undesirable system opera-
tion or sensor damage may result when using re-
placement equipment that is not of the same size,
type, and/or style. After-market wheels can cause
sensor damage. Do not use aftermarket tire sealants
or balance beads if your vehicle is equipped with a
TPMS, as damage to the sensors may result.
24. Odometer/Trip Odometer
The odometer shows the total distance the vehicle has
been driven.
UNDERSTANDING YOUR INSTRUMENT PANEL 211
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NOTE:Magnetic materials should be kept away from
the top of the instrument panel above the radio. This is
where the compass sensor is located.
Automatic Compass Calibration
The self-calibrating feature of the compass eliminates the
need to calibrate the compass for normal conditions.
During a short initial period, the compass may appear
erratic and the CAL symbol will appear (blinking) on the
display. After the vehicle has completed at least one
complete circle under 5 mph (8 km/h) in an area free
from large metal objects, calibration will be complete
when the CAL symbol is extinguished.
After initial calibration, the compass will continue to
automatically update this calibration whenever the ve-
hicle is in motion.
Manual Compass Calibration
NOTE: Before attempting a manual compass calibra-
tion, the engine must be running and the transmission
in the PARK position (if equipped).
If the compass seems in error or erratic, you may wish to
manually recalibrate the compass. To manually calibrate
the compass, you must first enter the variance mode.
Press and hold the left button (located on the instrument
cluster) for approximately 10 seconds to enter the vari-
ance mode, and release the button when the VAR (Com-
pass Variance) symbol appears. The current variance
value will also be displayed. Once in the variance mode,
it is necessary to release the button, and then press and
hold it again (approximately 10 seconds) until CAL is
displayed (solid, not blinking). Manual compass calibra-
tion has been initiated. Drive the vehicle slowly in one or
more circles under 5 mph (8 km/h) in an area free from
large metal objects until the CAL symbol is extinguished.
218 UNDERSTANDING YOUR INSTRUMENT PANEL

Tire pressure should be checked and adjusted as well as
inspecting for signs of tire wear or visible damage, at
least once a month. Use a good quality pocket-type gauge
to check tire pressure. Do not make a visual judgement
when determining proper inflation. Radial tires may look
properly inflated even when they are under inflated.
CAUTION!
After inspecting or adjusting the tire pressure always
reinstall the valve stem cap. This will prevent mois-
ture and dirt from entering the valve stem, which
could damage the Tire Pressure Monitoring Sensor.
Inflation pressures specified on the placard are always
“cold tire inflation pressure.” Cold tire inflation pressure
is defined as the tire pressure after the vehicle has not
been driven for at least three hours, or driven less than 1
mi (1 km) after a three hour period. The cold tire inflation
pressure must not exceed the maximum inflation pres-
sure molded into the tire side wall.
Check tire pressures more often if subject to a wide range
of outdoor temperatures, as tire pressures vary with
temperature changes.
Tire Placard Location (Four-Door Models)
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CAUTION!
The TPMS has been optimized for the original
equipment tires and wheels. TPMS pressures have
been established for the tire size equipped on your
vehicle. Undesirable system operation or sensor
damage may result when using replacement equip-
ment that is not of the same size, type, and/or style.
Aftermarket wheels can cause sensor damage. Do not
use aftermarket tire sealants or balance beads if your
vehicle is equipped with a TPMS, as damage to the
sensors may result.
CAUTION!
After inspecting or adjusting the tire pressure always
reinstall the valve stem cap. This will prevent mois-
ture and dirt from entering the valve stem, which
could damage the Tire Pressure Monitoring Sensor.
NOTE:
•The TPMS is not intended to replace normal tire care
and maintenance, nor to provide warning of a tire
failure or condition.
•The TPMS should not be used as a tire pressure gauge
while adjusting your tire pressure.
•Driving on a significantly under-inflated tire causes
the tire to overheat and can lead to tire failure.
Under-inflation also reduces fuel efficiency and tire
tread life, and may affect the vehicle’s handling and
stopping ability.
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•The TPMS is not a substitute for proper tire mainte-
nance, and it is the driver ’s responsibility to maintain
correct tire pressure, even if under-inflation has not
reached the level to trigger illumination of the Tire
Pressure Monitoring Telltale Light.
•Seasonal temperature changes will affect tire pressure,
and the TPM System will monitor the actual tire
pressure in the tire.
Base System
The Tire Pressure Monitor System (TPMS) uses wireless
technology with wheel rim-mounted electronic sensors to
monitor tire pressure levels. Sensors, mounted to each
wheel as part of the valve stem, transmit tire pressure
readings to the Receiver Module.
NOTE:It is particularly important, for you to check the
tire pressure in all of your tires regularly and to maintain
the proper pressure. The Tire Pressure Monitor System (TPMS) consists of the
following components:
•Receiver Module
•Four Tire Pressure Monitoring Sensors
•Tire Pressure Monitoring Telltale Light
A tire pressure monitoring sensor is located in the spare
wheel if the vehicle is equipped with a matching full size
spare wheel and tire assembly. The matching full size
spare tire can be used in place of any of the four road
tires. A low spare tire will not cause the Tire Pressure
Monitoring Telltale Light to illuminate or the chime to
sound. The Tire Pressure Monitoring Telltale Light will
illuminate in the instrument cluster, and an au-
dible chime will be activated when one or more of
the four active road tire pressures are low. Should this
occur, you should stop as soon as possible, check the
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inflation pressure of each tire on your vehicle, and inflate
each tire to the vehicle’s recommended cold placard
pressure value. The system will automatically update
and the Tire Pressure Monitoring Telltale Light will
extinguish once the updated tire pressures have been
received. The vehicle may need to be driven for up to 10
minutes above 15 mph (25 km/h) to receive this infor-
mation.
The Tire Pressure Monitoring Telltale Light will flash on
and off for 75 seconds, and will remain on solid when a
system fault is detected. The system fault will also sound
a chime. If the ignition key is cycled, this sequence will
repeat, providing the system fault still exists. A system
fault can occur by any of the following scenarios:
1. Jamming due to electronic devices or driving next to
facilities emitting the same Radio Frequencies as the TPM
sensors.
2. Installing some form of aftermarket window tinting
that affects radio wave signals.3. Lots of snow or ice around the wheels or wheel
housings.
4. Using tire chains on the vehicle.
5. Using wheels/tires not equipped with TPM sensors.
NOTE:
If your vehicle is equipped with a matching
full-size spare wheel and tire assembly, it has a tire
pressure monitoring sensor, and can be monitored by the
Tire Pressure Monitoring System (TPMS). In the event
that the matching full-size spare tire is swapped with a
low pressure road tire, the next ignition key cycle will
still show the Tire Pressure Monitoring Telltale Light to
be ON, and a chime to sound. Driving the vehicle for up
to 10 minutes above 15 mph (25 km/h) will turn OFF the
Tire Pressure Monitoring Telltale Light as long as none of
the road tires are below the low pressure warning thresh-
old.
334 STARTING AND OPERATING