Detects that it is being driven at an irregularly slower speed than the specified value.
Encoder cable is damaged.
Motor cable is damaged.
Check points and solutions :
Check if there is some foreign material causing extra load between the PF Motor and the PF roller. Check the connection between the PF Encoder Sensor and the Main Board Assy. Check the connection between the PF Motor and the Main Board Assy. Replace the PF Encoder Sensor. Replace the PF Motor.