Component description

RDC control unit

Fully diagnosis-compatible

Task:

evaluates the following telegrams from the wheel electronic units:

tire pressure
tire air temperature
identification number (ID) of wheel electronic unit
remaining service life of wheel electronic unit battery

If required, information or a warning is transmitted.

Fig 1: RDC Control Unit

Courtesy of BMW OF NORTH AMERICA, INC.

Wheel electronic unit with valve

Components:

pressure sensor
temperature sensor
transmitter
- frequencies according to country
power supply

service life: approx. 7 years
not exchangeable

Fig 2: Wheel Electronic Unit With Valve

Courtesy of BMW OF NORTH AMERICA, INC.

Installation location of wheel electronic unit in disc wheel

The wheel electronic unit (1) is screwed to the valve (2) on the disc wheel (3)

Identifying feature:

metal tire valves

NOTE: Different valves have to be used to allow for the different disc wheel sizes. The valves are color-coded. The correct coding can be taken from the spare parts catalogue.

Fig 3: Wheel Electronic Unit Installation Location In Disc Wheel

Courtesy of BMW OF NORTH AMERICA, INC.

Antenna

There is an antenna in each wheel housing.

Task:

receives telegrams and forwards these to the RDC control unit.

Fig 4: Antenna

Courtesy of BMW OF NORTH AMERICA, INC.

Component description

Set button

Installed in the instrument panel to the right of the steering wheel. (E46: in the center console)

Symbol: tire cross-section

Task:

initialization after resetting cold tire pressure or after changing tire or wheel location.

Fig 5: Locating Set Button

Courtesy of BMW OF NORTH AMERICA, INC.

Display element in instrument cluster

Indicator lamp lights up yellow:

drop in tire pressure of 0.2 to 0.4 bar
Indicator lamp lights up red:
drop in tire pressure greater than 0.4 bar

Fig 6: Locating Display Element In Instrument Cluster

Courtesy of BMW OF NORTH AMERICA, INC.