FE17, This onitoring feature is activated immediately after
the vehicle is switched on.
The voltage at the field (1) of the drive motor should
be about half the voltage (UBatt/2) at the armature
(VMN = UBatt).
In order for the error to be initiated, the voltage
deviation must be more than 4.4 volts and continue
for more than 2 seconds.
The voltage at the field must definitely be more than
4.4 volts.

FE42 The control system (logic board) makes available an
output that is active when the main contactor is
closed. It is deactivated when the main contactor is
open.
This output is checked for a short-circuit every 8 ms.
This output is also described as "Controller started
successfully".
The output is sent to the LAS module via a ribbon
cable (connector X20).
If this information is not applied at the LAS module,
this blocks all the functions, since the safety monitor
of the module

I guess you've replace logic card inside FPS module so it's possible you have a faulty motor or power stage in FPS module.


FE55 is indicating that thas not been made the teach in process for different hydraulics potentiometers (hydraulics levers)

Good luck