Daikin Mini-Split Code E4
Soft lockout
Actuation of low pressure sensor. Suction pressure fell below about 0.07 MPa, so the control stopped the compressor.
Manual wording: “E4 Actuation of low pressure sensor”
Documented for: RMXS multi-split outdoor units
Likely causes, most common first
- Abnormal drop of low pressure (lower than 0.07 MPa)
- Defective low pressure sensor
- Defective outdoor unit PCB
- Stop valve not opened
What you can safely check yourself
- Check and replace the indoor unit air filters (starved airflow drops suction pressure)
- Make sure indoor unit airflow is not blocked
- Check the outdoor unit is clear of snow and debris
When to call a technician
E4 usually means low refrigerant charge, a closed stop valve or a restriction. All of those need a technician with gauges.
A Daikin mini-split throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Source
- Service Manual - Multi-Split Type Air Conditioners RMXS-L Series (SiUS181631EA) (Daikin, RMXS48LVJU outdoor, BPMKS048A2U/049A3U branch provider, CTXG/CTXS/FTXS/CDXS/FDXS/FVXS/FFQ indoor units) · checked 2026-08-25