152 Instruments, On-Board Computer, Warnings
No monitoring
In the event of faults the Tire Pressure Monitoring
cannot monitor the tire pressure.
The warning light in the speedometer flashes for
approx. one minute and then remains continuously
illuminated and a corresponding message
appears on the on-board computer.
Monitoring is not active when:
– the Tire Pressure Monitoring is faulty,
– wheel transmitters for the Tire Pressure
Monitoring are missing,
– during the learning phase after the tire settings
have been updated,
– after a wheel change without updating the tire
settings,
– more than four wheel transmitters are
detected,
– there is external interference by other radio
sources, e.g. wireless headphones,
– tire temperatures are too high.
f Please see the chapter “WARNINGS ON THE
INSTRUMENT PANEL AND THE ON-BOARD
COMPUTER” on Page 158.
Pressure increase as the result of
temperature increase
In accordance with physical principles, the air
pressure changes as the temperature changes.
The tire pressure increases or decreases by
around 1.5 psi (0.1 bar) for every 18 °F (10 °C)
change in temperature.
The Tire Pressure Monitoring takes this relation-
ship between tire pressure and temperature into
account.
Tire pressure specifications
Information on tire pressure for public roads can
be found in this Owner's Manual in the Technical
Data chapter or on the tire-pressure plate in the
left door aperture.
These values apply to cold tires at 68 °F (20 °C)
ambient temperature.
