Lennox Mini-Split Service Manual / Page 233
P4 Flow Chart
Compressor Drive Error
Check wiring connections between compressor and
main PCB.
No
Make necessary corrections.
Yes
Check the IPM
Replace the IPM board or replace the
main PCB.
No
Yes
Check the outdoor fan and the outdoor unit ventilation.
Refer to the fault code fan speed malfunc-
tion (E8).
No
Yes
Check the compressor resistance values.
Replace the compressor.
No
Yes
Replace the outdoor main PCB.