The tire pressure values indicated by the on-
board computer may differ from those
measured at a gas station with a pressure
gauge. The tire pressures shown by the on-
board computer refer to those measured at
sea level. At high altitudes, the tire pressure
values indicated by a pressure gauge are
higher than those shown by the on-board
computer.Inthis case, do not reduce the tire
pressures.
The operation of the tire pressure monitor can
be affected by interference from radio
transmitting equipment (e.g. radio
headphones, two-way radios) that may be
being operated in or near the vehicle.
Checking the tire pressure
electronically
XMake sure that the SmartKey is in position
2(Ypage 137) in the ignition lock .
XPress the or button on the
steering wheel to select theService
menu.
XPress the or button to select
Tire Pressure.
XPress the button.
The current tire pressure of each tire is
shown in the multifunction display.
If the vehicle has been parked for over
20 minutes, theTire pressure will be
displayed after driving a few
minutesmessage appears.
After a teach-in process, the tire pressure
monitor automatically detects new wheels or
new sensors. As long as a clear allocation of
the tire pressure value to the individual
wheels is not possible, theTire Pressure
Monitor Activedisplay message is shown
instead of the tire pressure display. The tire
pressures are already being monitored.
Tire pressure monitor warning
messages
If the tire pressure monitor detects a pressure
loss in one or more tires, a warning message
is shown in the multifunction display and the
yellow tire pressure monitor warning light
comes on.
RIf theCorrect Tire Pressuremessage
appears in the multifunction display, the
tire pressure in at least one tire is too low
and must be corrected at the next
opportunity.
RIf theCheck Tire Pressure Soon
message appears in the multifunction
display, the tire pressure in one or more
tires has dropped significantly and the tires
must be checked.
RIf theTire Pressure Warning Tire
Failuremessage appears in the
multifunction display, the tire pressure in
one or more tires has dropped suddenly
and the tires must be checked.
Observe the instructions and safety notes in
the display messages in the "Tires" section
(Ypage 234).
iIf the wheel positions on the vehicle are
rotated, the tire pressures may be
displayed for the wrong positions for a
short time. This is rectified after a few
minutes of driving, and the tire pressures
are displayed for the correct positions.
Restarting the tire pressure monitor
When you restart the tire pressure monitor,
all existing warning messages are deleted and
the warning lamps go out. The monitor uses
the currently set tire pressures as the
reference values for monitoring. In most
cases, the tire pressure monitor will
automatically detect the new reference
values after you have changed the tire
pressure. However, you can also define
reference values manually as described here.
The tire pressure monitor then monitors the
new tire pressure values.
322Tire pressure
Wheels and tires
