MRCOOL mini split error code EH 00
Indoor unit EEPROM parameter error. Also shown as EH00.
- TypeFault
- SystemControl board
- Can I fix it?Homeowner checks, then maybe a tech
- Applies toindoor unit display (four-character codes)
What EH 00 means on a MRCOOL
The indoor control board could not read its stored model parameters from memory. The unit will not run normally until it can.
On this platform, EH 00 is a fault: something has failed or is disconnected and needs diagnosis.
Common causes
- A surge or brownout corrupted the stored data.
- The indoor main board has failed.
- A replacement board was not programmed for the model.
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.
- 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.
- If the code comes straight back after a reset, the fault is real and not a glitch.
- If the board was recently replaced it needs the model parameters written with the service tool.
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 board fault. If two resets do not clear it, the indoor main board needs replacement or reprogramming.
Which MRCOOL units show EH 00
This page applies to MRCOOL DIY 2nd/3rd Gen, DIY 4th Gen, DIY Multi-Zone, Advantage, Olympus and Easy Pro units on the indoor unit display (four-character codes). MRCOOL's own documentation lists EH 00 as "Indoor unit EEPROM parameter error", the same definition used across the Midea platform (four-character codes) 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 MRCOOL shows this code
The indoor display shows the code in place of the temperature. On DIY 4th Gen units a four-character code alternates between its two halves (EL, then 0C); write down both. The MRCOOL app also reports the current fault.
EH and EL are indoor-side faults, EC is an outdoor-side fault, and PC is an outdoor protection: the unit stopped itself to prevent damage.
Other MRCOOL codes
Same part of the system as EH 00:
EH 00 on other brands
The same characters do not always mean the same thing. Check the brand on your unit.
- Pioneer EH 00 Indoor unit EEPROM parameter error
Questions people ask
Can I reset a MRCOOL EH 00 code myself?
Yes. Turn the system off at the breaker for five minutes, then restart it. If EH 00 comes back, the fault is real and needs the checks above.
Is it safe to keep running a MRCOOL showing EH 00?
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.
Do I need a technician for MRCOOL EH 00?
Work through the checks below first; they resolve most cases. If they do not, the repair itself may need a technician. A board fault. If two resets do not clear it, the indoor main board needs replacement or reprogramming.
Sources
- MRCOOL DIY 3rd Gen and 4th Gen installation manuals (error code tables)
- Midea residential split service manual
Updated September 2026. Codes and definitions vary by model year. If your manual disagrees with this page, your manual wins. Send a correction.