The yellow “Service Due” warning message lights up in the instrument cluster, even though the brake pad thickness is more than 4.2 mm (above the thickness at which the pad sensor intervenes). The calculated remaining service life for the brake pads (front and/or rear axle) from the CBS data does not match the actual brake pad thickness.
Software calculation of the brake pad wear model in the DSC.
1. Run vehicle diagnostics with ISTA/D and work through the corresponding test modules.
2. If there are no faults found (this must be resolved first), update the vehicle software using ISTA/P 2.51.0 or a more recent version.
3. Programming must be started under the conversion menu item “Brake pad correction CBS conversion.”
4. After programming, the vehicle CBS data must be corrected as follows:
a. Using ISTA, perform vehicle CBS data correction.
b. In the diagnostic menu item “Front/rear brake,” select “Reset forecast to 50,000 km” and reset the forecast distance.
c. Check the remaining brake pad thickness using special tool #34 1 260.
d. In the diagnostic menu item “Front/rear brake,” select “Set availability, enter the brake pad thickness” and enter the pad thickness measured in mm.
Courtesy of Mitchell 1.