[mk-echo]

Вот описания:

* The 1st image transfer pressure/retraction position sen-
sor doesn’t turn ON (retracting) even after the lapse of a
given period of time after the 1st image transfer pressure/
retraction clutch has turned ON during the transfer belt
unit is retracting.

* The 1st image transfer pressure/retraction position sen-
sor doesn’t turn OFF (pressuring) even after the lapse of
a given period of time after the 1st image transfer pres-
sure/retraction clutch has turned ON during the transfer
belt unit is pressuring.

Грубо говоря, что-то с прижиманием IU к ремню переноса.
Смотреть засоры в клатчах, шестеренках.
м.б. сломанный клатч (clutch) - тогда бывает плавающая ошибка, то работает, то нет. проверяется заменой клатча.