Pioneer YN018GMFI16M2D Service Manual page 54

Pic 1:Use a multimeter to test the
DC voltage between L2 port and S
port of outdoor unit. The red pin of
multimeter connects with L2 port
while the black pin is for S port.
When AC is normal running, the
voltage will move alternately
between positive value and
negative value.
Pic 2: :IPM (For dual/tri-zone)
Operating
Self‐Check