General Information On Wheel Electronics

The Tire Pressure Monitoring system is designed to constantly monitor the Tire pressure during driving and when the vehicle is stationary. One wheel electronics unit -A-  per Tire is mounted in the rim well base. These measure Tire pressure and temperature at regular intervals and transfer the values to a central control unit via a high-frequency route. The control unit evaluates the information and transfers the data to the instrument cluster if required. In this way, the driver is warned and informed if the Tire pressure needs to be corrected.

There are different types of wheel electronics units -A-  . Some of these are not compatible and send signals in various frequencies.

Information 

To differentiate the wheel electronics, a table is stored in GFF (Guided Fault Finding) in the Porsche System Tester. Please note the following path:

• Select Fault finding>>Vehicle type>>Model year>>Model>>TPM>>Guided Fault Finding. Press the Jump key (footprints). Select Function/component selection>>Chassis>>TPM>>Inspections/tests>>Wheels/tires>>Wheel electronics>>Nominal values button<<. 

The following points can also be used as distinguishing characteristics:

• The labelling - 433 MHz or 315 MHz, depending on country classification
• The part number
• TPM system and wheel electronics generation
• The colour of the housing up to and including model year 2006/1st generation (433 MHz - dark grey and 315 MHz - light grey)
• The colour of the housing up to and including model year 2006/1st generation (433 MHz - orange and 315 MHz - dark brown)
• 2 x 4 stars for enhanced transmission power up to and including model year 2006
• The colour of the housing as of model year 2008/2nd generation (433 MHz - dark grey and 315 MHz - light grey)
• No stars on the housing as of model year 2008

2nd generation wheel electronics units with a slightly modified housing are used as of model year 2008.

The wheel electronics units as of model year 2008 are not compatible with the wheel electronics units up to model year 2006. In other words:

• The new system does not recognise wheel electronics units up to model year 2006/1st generation
• The old system does not recognise wheel electronics units as of model year 2008/2nd generation

Fig 1: Identifying Valve And Wheel Electronics Components

Courtesy of PORSCHE CARS NORTH AMERICA, INC.

1. Wheel electronics
2. Valve complete (No. 2 to No. 7)

1. Self-locking (Torx) fastening screw
2. Valve cap (plastic)
3. Valve insert
4. Union nut
5. Washer chamfered on both sides
6. Bead seat sealing ring
7. Valve