Samsung ERV - Supply Air Fan Error

Samsung Electronics 9-5
Error Mode Supply air fan error
Display
Check Method ERROR occurs, if Motor RPM is lower than 120 RPM for about 40 seconds.
Cause PCB check, Motor check
Sensor SPEC. Motor RPM outputs square wave.
9-4-3 Supply Air Fan Error
Check product
operation
No
Is Motor connector (CN74)
of PCB dislocated from PCB?
Assembly connector
Yes
No
Does Motor rotate in case of operation?
Is DC0V~DC6V power measured
from Motor ③↔⑤?
PCB check or replacement
Is Motor RPM is lower
than 120?
Yes
E561 code appears when
unit operation starts or while it is in operation.
No
Motor check or
replacement
Yes