No
Yes
Check if the wiring between the main PCB
and the compressor are connected
incorrectly and if the wires or connectors are
broken. Were any connections loose or off?
Error Code
P4
–
Compressor and/or Inverter Problem
Indoor Unit or Wired Control Display
–
P4
Dr. Smart Display (Debugger)
–
P4, P43
Malfunction decision conditions
An abnormal inverter compressor drive is detected
by a special detection circuit, including
communication signal detection, voltage detection
and compressor rotation speed signal detection.
Supposed Causes
• Wiring mistake
• IPM malfunction
• Outdoor fan assembly fault
• Compressor malfunction
• Outdoor PCB faulty
Troubleshooting:
Error is only displayed every 3 minutes, during this time you may
see either “normal display” or “88” on indoor unit or wired control.
Follow the “1st Steps for DLS Troubleshooting”
in the beginning of this guide, if you have an
active error, procedure below.
Inverter Compressor Drive Error P4
All Single Zone Outdoor Units
Correct the connections or
replace the wires and connectors.
Meg & Ohm the compressor, see
Compressor Checks 1 & 2.
Did Compressor Meg out correctly?
No
Yes
Replace the IPM (Inverter) board
OR replace the main PCB if the
IPM board and the main PCB are
integrated together.
Dr. Smart
Display
Replace both compressor & the IPM
(Inverter) board OR replace the
main PCB if the IPM board and the
main PCB are integrated together.
If after parts
replacement, P4 is still
displayed, contact your
local CE Technical
Support Rep.
