Re: selespeed actuator
Juz sharing my experience with Selespeed.
If selespeed only allows you to engage till 2nd gear, it is called "link home mode". Use examiner to check on the error code (Selespeend System Failure).
In my case, examiner points to the disc speed error (no reading at all). Hence, replace the disc speed sensor plus cleaning of contact. Then follow by a re-calibration.
From my info gathered on the actuator failure, it is usually due to leak (pin hole at diaphragm) which cause the pressure to be out of spec between 40 and 55 bar. Else MTBF is around 80K km.