Auxiliary Driving Systems; Tire Pressure Monitoring System (Tpms) - RAM Commercial Promaster 2018 User Manual

AUXILIARY DRIVING SYSTEMS

Tire Pressure Monitoring System
(TPMS)
The Tire Pressure Monitor System (TPMS)
will warn the driver of a low tire pressure
based on the vehicle recommended cold
placard pressure.
The tire pressure will vary with temperature
by about 1 psi (7 kPa) for every 12°F (6.5°C).
This means that when the outside tempera-
ture decreases, the tire pressure will de-
crease. Tire pressure should always be set
based on cold inflation tire pressure. This is
defined as the tire pressure after the vehicle
has not been driven for at least three hours, or
driven less than 1 mile (1.6 km) after a three
hour period. The cold tire inflation pressure
must not exceed the maximum inflation pres-
sure molded into the tire sidewall. Refer to
"Tires" in "Servicing And Maintenance" 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.
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The TPMS will warn the driver of a low tire
pressure if the tire pressure falls below the
low-pressure warning limit for any reason,
including low temperature effects and natu-
ral 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 the recommended
cold placard pressure. Once the low tire pres-
sure warning (Tire Pressure Monitoring [TPM]
Telltale Light) illuminates, you must increase
the tire pressure to the recommended cold
placard pressure in order for the TPM Telltale
Light to turn off. The system will automati-
cally update and the TPM Telltale Light will
turn off once the system receives the updated
tire pressures. The vehicle may need to be
driven for up to 20 minutes above 15 mph
(24 km/h) in order for the TPMS to receive
this information.
NOTE:
When filling warm tires, the tire pressure may
need to be increased up to an additional 4 psi
(28 kPa) above the recommended cold plac-
ard pressure in order to turn the Tire Pressure
Monitoring Telltale Light off.
For example, your vehicle may have a recom-
mended cold (parked for more than three
hours) placard pressure of 30 psi (207 kPa).
If the ambient temperature is 68°F (20°C)
and the measured tire pressure is 27 psi
(186 kPa), a temperature drop to 20°F (-7°C)
will decrease the tire pressure to approxi-
mately 23 psi (158 kPa). This tire pressure is
sufficiently low enough to turn on the TPM
Telltale Light. Driving the vehicle may cause
the tire pressure to rise to approximately
27 psi (186 kPa), but the TPM Telltale Light
will still be on. In this situation, the TPM
Telltale Light will turn off only after the tires
are inflated to the vehicle's recommended
cold placard pressure value.