DIY HVAC Tools

EG4 mini split error code 05

Outdoor unit data error (EEPROM). Also shown as 5.

  • TypeFault
  • SystemControl board
  • Can I fix it?Technician job

What 05 means on a EG4

The outdoor board could not read valid stored data.

On this platform, 05 is a fault: something has failed or is disconnected and needs diagnosis.

Common causes

  • A surge or lightning event.
  • A failed outdoor board.

How to fix it yourself

Do the reset and the visual checks, but the underlying repair needs a technician with a meter and the service manual.

  1. Reset the system: switch the breaker (or the outdoor disconnect) off, wait a full five minutes so the boards fully discharge, then switch it back on and restart from the remote.
  2. If the code comes straight back after a reset, the fault is real and not a glitch.

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

Board replacement or reprogramming.

Which EG4 units show 05

This page applies to EG4 12K hybrid solar mini split (AC/DC, R32) and 12K / 24K hybrid mini split AC/DC R32 (DWA4 / DWB3 / DGA) units. EG4's own documentation lists 05 as "Outdoor unit data error (EEPROM)", the same definition used across the EG4 hybrid solar mini split 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 EG4 shows this code

The indoor unit's LED display shows a two-digit number in place of the temperature. EG4 units also run on DC from solar panels, so several codes concern the DC input and the power stage rather than the refrigerant side. 01 to 06 are indoor and communication faults, 31 to 37 are temperature sensors, 51 to 58 are motors, 72 to 79 are voltage and current protections, and 81 to 96 are inverter and compressor drive faults.

Other EG4 codes

Same part of the system as 05:

01Indoor unit data error (EEPROM)04Indoor unit buttons stuck83AD (analog) detection abnormal85Compressor setting data wrong
03Communication error between indoor and outdoor units06Indoor fan motor fault31Indoor air (room) temperature sensor fault (open or short circuit)32Indoor evaporator temperature sensor fault (open or short circuit)35Outdoor air temperature sensor fault (open or short circuit)36Outdoor condenser temperature sensor fault (open or short circuit)37Air outlet temperature sensor fault (open or short circuit)51Indoor fan motor lost speed

All EG4 error codes

Questions people ask

Can I reset a EG4 05 code myself?

Yes. Turn the system off at the breaker for five minutes, then restart it. If 05 comes back, the fault is real and needs the checks above.

Is it safe to keep running a EG4 showing 05?

The unit will usually refuse to run, or run with reduced output, until the fault is cleared. Repeated resets do not fix anything and can mask a problem that is getting worse.

What will a technician check for 05?

Board replacement or reprogramming. Ask for the measurements, not just a parts quote.

Sources

  • EG4 12K Hybrid Solar Powered Mini-Split R32 User Manual (2025), section 14.3 Indoor Unit LED Error Codes
  • EG4 12K / 24K Hybrid Mini-Split AC/DC R32 User Manual (10/2025)

Updated September 2026. Codes and definitions vary by model year. If your manual disagrees with this page, your manual wins. Send a correction.