Daikin mini split error code E4
Low pressure protection.
- TypeProtection
- SystemRefrigerant circuit
- Can I fix it?Homeowner checks, then maybe a tech
What E4 means on a Daikin
Suction pressure fell below the limit. Usually low charge or a restriction. The compressor stops.
On this platform, E4 is a protection: the system stopped or throttled itself to prevent damage; many clear on their own once conditions return to normal.
Common causes
- Low charge from a leak.
- A service valve not fully open.
- A kinked line set.
- A frozen indoor coil.
How to fix it yourself
Work through the checks below first; they resolve most cases. If they do not, the repair itself may need a technician.
- Open both service valves fully.
- Pull the front panel and check the filters and the indoor coil. Dirty filters and a matted coil restrict airflow, and airflow problems trigger a surprising number of protection codes.
- If the indoor coil is iced, run Fan-only until it thaws.
- Leak-check the flare joints with soapy water.
- Anything inside the refrigerant circuit (sensors are fine, but valves, compressors and leaks are not) needs EPA-certified refrigerant handling. That is a technician job.
Switch off power at the breaker before opening either unit. Capacitors in the outdoor unit hold a charge for several minutes after power is cut.
When to call a technician
A technician must measure the charge and find the leak.
Which Daikin units show E4
This page applies to Daikin Aurora, 19 Series, Atmosphera, Emura, Quaternity and MXS multi-zone units. Daikin's own documentation lists E4 as "Low pressure protection", the same definition used across the Daikin it is built on. If your unit shows a code with a different shape (for example a four-character code, or a plain number), it is from a different table; use the lookup with your exact code.
Where Daikin shows this code
Most Daikin wall units do not show the code on the unit; the operation lamp blinks. To read the code, point the remote at the unit, hold CANCEL (or Timer Cancel) for about 5 seconds until 00 shows, then press CANCEL repeatedly. Each press shows a code; when the unit gives a long continuous beep instead of two short beeps, the code on the remote is the stored fault. Units with a wired controller show the code directly. A and C codes are indoor-unit faults, E, F, H, J, L and P codes are outdoor-unit faults and protections, and U codes are system-level problems such as communication, power supply and refrigerant shortage.
Other Daikin codes
Same part of the system as E4:
E4 on other brands
The same characters do not always mean the same thing. Check the brand on your unit.
- Pioneer E4 Indoor room temperature sensor (T1) open or short circuit / Outdoor temperature sensor fault: coil (T3), ambient (T4), discharge (T5) or a zone coil outlet (T2B)
- Blueridge E4 Compressor discharge temperature too high / Indoor room temperature sensor (T1) open or short circuit
- Gree E4 Compressor discharge temperature too high
- Zone Air E4 Abnormal system operation or lack of refrigerant
- Mitsubishi Electric E4 Indoor unit signal receiving error (from remote controller)
- Carrier E4 Indoor room temperature sensor (T1) open or short circuit
- Trane E4 Abnormal system operation or lack of refrigerant / Indoor unit signal receiving error (from remote controller)
- Heil E4 Indoor room temperature sensor (T1) open or short circuit / Compressor discharge temperature too high
- ACiQ E4 Indoor room temperature sensor (T1) open or short circuit / Abnormal system operation or lack of refrigerant
- Goodman E4 Low pressure protection
Questions people ask
Can I reset a Daikin E4 code myself?
Yes. Turn the system off at the breaker for five minutes, then restart it. If E4 comes back, the fault is real and needs the checks above.
Is it safe to keep running a Daikin showing E4?
Not repeatedly. A protection code means the unit stopped itself to prevent damage, and resetting it over and over can turn a cheap repair into a compressor failure. Reset once, check the basics, and stop if it returns.
Do I need a technician for Daikin E4?
Work through the checks below first; they resolve most cases. If they do not, the repair itself may need a technician. A technician must measure the charge and find the leak.
Sources
- Daikin residential (RA) service manuals (error code tables)
- Daikin operation manuals (remote controller self-diagnosis)
Updated September 2026. Codes and definitions vary by model year. If your manual disagrees with this page, your manual wins. Send a correction.