Removing and Installing Wheel Electronics
Removing and installing wheel electronics
The tyre pressure monitoring system is designed to constantly monitor the tyre pressure when the car is moving and stationary. One set of wheel electronics -A- per tyre is mounted in the rim well base. These electronics measure tyre pressure and temperature at regular intervals and transfer the values to a central control module via a high-frequency route. The control module evaluates the information and transfers the data to the instrument cluster if required. In this way, the driver is warned and informed if the tyre pressure has to be corrected.
There are various versions of the wheel electronics -A-. The electronics used in the Cayenne have a stronger transmission power. These transmit on a high frequency range of:
^ 433 MHz or 315 MHz.
The following points can be taken as distinguishing features:
^ The inscription, 433 MHz or 315 MHz
^ The part number
^ Every four stars left and right of the slot (only wheel electronics with stronger transmission power)
^ And/or the colour (dark grey 433 MHz/light grey 315 MHz)
Removal
Note!
^ In vehicles containing the lyre pressure monitoring system, the valve and wheel electronics are only replaced in exceptional cases! The following points can make replacement necessary!
Valve must be completely replaced with screw -1 to 7- if:
^ The wheel electronics are removed
^ The self-locking -1- fastening screw is loose
^ The bead seat sealing ring -6- is porous or damaged
^ The valve body -7- is distorted
^ The union nut-4- is loose
The wheel electronics -A- must be replaced if:
^ The housing is visibly deformed
^ The filter surface (square, porous section on back of wheel electronics) is so badly soiled that it can no longer be cleaned by wiping
^ Tyre sealant (tyre sealing liquid) has been used
^ The service life of the battery has expired
^ There is a fault within the wheel electronics.
When the tyre is removed, the wheel electronics -A- become visible in the outer rim well base, at the valve.
1. Release wheel electronics from valve with an inner Torx screwdriver T 20 (if necessary, counter with a suitable assembly pin, e.g. steel pin [diameter] approximately 1.8 mm, in bore at valve foot) and remove.
2. Then unscrew union nut and remove valve.
Installation
^ When replacing the wheel electronics, always use a completely new valve and a new fastening screw!
^ The tightening torque wheel for the electronics/valve is 4 Nm (3 ft. lbs.) (± 0.5 Nm (0.5 ft. lbs.))!
^ The wheel electronics must not come into contact with the tyre fitting paste or solvent!
^ Each time a gear set or wheel is changed this must be communicated to the control module, in particular if the positions of the wheels have been changed. The tyre type and tyre size must always be selected in the instrument cluster under Main menu > Tyre pressure > Settings. During the journey the control module then re-learns the wheel positions.
1. Install wheel electronics loosely at the valve (do not tighten) and position in the valve bore together with the valve and bead seat sealing ring.
Caution! Remove assembly pin after installing valve! Otherwise the lyre will be damaged during fitting.
Tighten the valve only once to the stipulated torque in the rim.
2. Position the washer that has been chamfered on both sides and screw on the union nut as far as the mounting face. Visibly twist bore at valve foot. If necessary, block with suitable assembly pin. The tightening torque is 4 Nm (3 ft. lbs.) (± 0.5 Nm (0.5 ft. lbs.)).
3. Push wheel electronics -A- slightly into rim well (this adjusts the angle of inclination of valve to wheel electronics).
4. Carefully tighten self-locking (Torx) fastening screw T 20 with tightening torque 4 Nm (3 ft. lbs.) (± 0.5 Nm (0.5 ft. lbs.)). The wheel electronics should now be lying evenly against the rim.