Component description

RD. 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: Identifying RD. 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: Identifying 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

Fig 3: Identifying Wheel Electronic Unit, Valve And 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 RD. control unit.

Fig 4: Identifying Antenna

Courtesy of BMW OF NORTH AMERICA, INC.

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 1: 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 2: Display Element In Instrument Cluster

Courtesy of BMW OF NORTH AMERICA, INC.