What It Means
Inverter compressor drive circuit error detected.
Carrier Ductless Mini-Split
Carrier Ductless Mini-Split Error Code P4
Troubleshooting guide for the Carrier Ductless Mini-Split system fault P4.
Possible Causes
- Shorted or open compressor windings.
- Supply voltage out of operating specification.
- Damaged inverter drive circuit on outdoor control board.
Not sure which one it is — or if it's none of these? Try ACLogics today.
Disclaimer: This information is for general reference. Error codes can vary by model and production year. Always refer to your machine's specific manual and the information printed on the unit itself.
New to this code? Click to see why this happens
Full Diagnosis
Inverter Compressor Drive Error. Abnormal inverter compressor drive detected by special detection circuit.
All Recorded Causes
Check compressor wiring for shorts or open circuits. Verify supply voltage is within specification. Inspect outdoor control board inverter drive circuit for damage. Replace outdoor control board or compressor as needed.
Verify Before Replacing Parts
- Confirm the exact Carrier model family and ductless systems context before acting on a generic code description.
- Confirm board LEDs, wiring polarity, and model compatibility before replacing control boards — this Carrier fault points at check compressor wiring for shorts or open circuits.
- Check for intermittent communication faults caused by connectors, moisture, or damaged harnesses, and rule out verify supply voltage is within specification.
- After the correction, run the system long enough to confirm the ductless systems fault does not return under normal load.
Still unsure about this fault?
ACLogics walks you through Carrier Ductless Mini-Split diagnostics step-by-step — so you confirm the cause before swapping parts.
