Special Notes For Tyre Pressure Monitoring (Tpm)
NOTIFICATION
Wheel electronics
- Wheel electronics unit and valve may have been fitted incorrectly.
- Wheel electronics units may not have been assigned correctly.
Read and follow the installation instructions for the wheel electronics units.
- → > 443219 REMOVING AND INSTALLING WHEEL ELECTRONICS
Check that the wheel electronics units are assigned correctly.
- → > Refer to approrpiate service Information
Information
Overview of wheel electronics
- If the old wheels are still near the vehicle after assembly work (for example changing winter tyres and/or wheels from another vehicle with TPM), these will still be detected by the system. If one or more of these wheels has a minimum pressure of more than 0.5 bar (7 psi) below the required pressure, this can trigger a warning in the instrument cluster. In this case, remove the wheels or adjust the vehicle outside the radio range of these wheels using the PIWIS Tester.
- Before changing a tyre, read out the remaining life span of the wheel electronics unit (battery capacity) using the PIWIS Tester.
- For vehicles with Tyre Pressure Monitoring (TPM), the valve and wheel electronics -arrow- are only replaced in exceptional cases. The following points can make replacement necessary.
3rd generation wheel electronics
| 1 | Self-locking (Torx) screw - replace |
| 2 | Wheel electronics |
| 3 | Valve, complete (No. 5 to No. 7) |
| 4 | Valve cap |
| 5 | Valve body with valve insert |
| 6 | Double chamfered washer |
| 7 | Union nut |
| 8 | Wheel electronics assembled |
Valve must be replaced complete with screw -1, 2, 3- if:
- The wheel electronics unit is removed
- The self-locking screw -1- is loose
- The valve body -5- is bent
- The union nut -7- is loose.
The wheel electronics unit -2- must be replaced if:
- The housing is visibly deformed
- The filter surface (round, porous section on back of wheel electronics) is so badly soiled that it can no longer be cleaned by wiping
- Tyre sealing compound (tyre sealing liquid) has been used
- The service life of the battery is exceeded
- There is a fault inside the wheel electronics unit.