Programmable, see 31.35 Motor feedback fault.

Selected motor, no motor speed feedback is received. See also
A7B0.
Check the auxiliary code (format XXYY ZZZZ).
XX specifies the location of the speed feedback device. Either
an encoder interface module or the control board.
01: Encoder interface module 1, see parameters 91.11 and
91.12.
02: Encoder interface module 2, see parameters 91.13 and
91.14.
03: Control board, see group 94 OnBoard speed feedback
configuration.
YY specifies the speed feedback device.
01: Encoder 1, see group 92 Encoder 1 configuration.
02: Encoder 2, see group 93 Encoder 2 configuration.
03: OnBoard encoder, see group 94 OnBoard speed feedback
configuration.
04: Tacho, see group 94 OnBoard speed feedback
configuration.
ZZZZ indicates the problem.