It is nice to read posts about anything, for example because this post today I know that I can't rotate tires without programming the TPMS, I never think about this before.
How you program the TPMS to tell what tire is located in front, back, right or left?
Some cars don't use a TPMS to detect if a tire is low, you can't view the exact tire pressure but the car warns you when the tire is low. I think this cars uses some very smart calculation between rotation, timing, miles, etc, to detect when the tire is low, you only need to reset the tire warning indicator when you fill your tires.
There is some good information about how the TPMS works in your Town and Country Manual, read page 368 STARTING AND OPERATING. I like to read the manual in my computer that way you can use search, and view pages in a better way. If you don't have it in PDF search in here for one it is very useful and you could read it on your iphone too.
TIRE PRESSURE MONITOR SYSTEM (TPMS)
The TPMS will warn the driver of a low tire pressure
based on the cold inflation tire pressure requirements
found on the tire placard located on the driver’s-side
B-pillar.
The tire pressure will vary with temperature by about 1
psi (6.9 kPa) for every 12 F (6.5 C). This means that when
the outside temperature decreases, the tire pressure will
decrease. Tire pressure should always be set based on
cold inflation tire pressure. This is defined as the tire
pressure after a vehicle has not been driven for more than
three hours - and in outside ambient temperature. Refer
to the “Tires – General Information” in this section for
information on how to properly inflate the vehicle’s
tires. The tire pressure will also increase as the vehicle is
driven - this is normal and there should be no adjustment
for this increased pressure.
The TPMS will warn the driver of a low tire pressure if
the tire pressure falls below the low pressure warning
threshold for any reason, including low temperature
effects, or natural air pressure loss through the tire.
The TPMS will continue to warn the driver of low tire
pressure as long as the condition exists, and will not turn
off until the tire pressure is at or above recommended
cold tire placard pressure. Once the low tire pressure
warning has been illuminated, the tire pressure must be
increased to the recommended cold tire placard pressure
in order for the TPMS warning lamp to be turned off. The
system will automatically update and the TPMS warning
lamp 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 information.
For example, your vehicle may have a recommended
cold (parked for more than three hours) tire pressure of
35 psi (241 kPa). If the ambient temperature is 68 F (20 C)
and the measured tire pressure is 30 psi (207 kPa), a
temperature drop to 20 F (-7 C) will decrease the tire
pressure to approximately 26 psi (179 kPa). This tire
pressure is sufficiently low enough to turn ON the TPMS
Warning Light. Driving the vehicle may cause the tire
pressure to rise to approximately 30 psi (207 kPa), but the
TPMS Warning Light will still be ON. In this situation,
the TPMS Warning Light will turn OFF only after the tires
have been inflated to the vehicle’s recommended cold tire
pressure value.
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 sealants or balance beads if your
vehicle is equipped with a TPMS, as damage to the
sensors may result.