MrCool Error Codes: DIY and Advantage Code Tables

MrCool error codes are letter and number codes on the indoor unit's display, such as EL 01 or PC 03 on 4th Gen and newer DIY units, or E1 and P6 on Gen 1 to 3 units. Units without a display flash the operation lamp instead. MrCool's manuals give one first step for any code: wait about 10 minutes, and if it does not clear, disconnect the power, reconnect it and turn the unit back on. If the code comes back, call MrCool or a technician.

How to read a MrCool error code

MrCool's guide on finding an error code on a mini split lists four places a code can show up:

• The indoor display: most units show the code on the front panel.
• Flashing lamps: count the flashes and match them to your manual.
• The remote: on some models, turn the unit off, then hold LED or TEMP for 5 to 10 seconds. The button varies by model.
• The SmartHVAC app: Wi-Fi units can show the code on your phone.

Some outdoor units also show codes on a control board behind the electrical panel. MrCool's guide says to switch the breaker off before opening that panel. We suggest leaving the panel to a technician.

Write down the full code and the model number from the unit's label. The tables below differ by generation.

What MrCool tells every owner to do first

The DIY Select owner's manual (August 2026) and the Advantage manuals give the same order of checks:

1. Wait about 10 minutes. The unit may stop or keep running in a safe mode, and the code may clear itself.
2. If it does not, disconnect the power, connect it again and turn the unit on.
3. If the code persists, disconnect the power and contact MrCool.

Before you blame the unit, rule out the simple things the same manual lists. The unit will not restart for 3 minutes after it is turned off. A timer may be set. The remote batteries may be dead. A dirty filter or a blocked air inlet or outlet hurts cooling. MrCool says to clean the filter every two weeks, and to turn the unit off and disconnect the power first. Our guide to resetting an air conditioner covers the power cycle.

Turn the unit off and call for service if a wire is damaged or warm, you smell burning, you hear loud or abnormal sounds, the breaker trips often, or water falls out of the unit. The manual says not to fix these yourself.

MrCool DIY 4th Gen error codes

Codes from MrCool's DIY E Star 4th Gen owner's manual (version 03-21-23), with the operation lamp flashes the manual pairs with each code. The timer lamp stays off unless noted. MrCool's warning sits under the table: the code list is for reference, and you should turn the unit off and contact a qualified technician rather than attempt these repairs.

MrCool prints the same lamp pattern for PC 00 and PC 03, so read the display rather than the flashes when you can. If the display shows a garbled code or one that is not in the manual, MrCool says to make sure it is not a temperature reading first.

What changes on the DIY Select (5th Gen) units

The DIY Select manual uses the same EH, EL, EC and PC codes, with a few new ones and some new wording. These match MrCool's 5th Gen error code list:

• EH 0A: indoor EEPROM parameter error. EH 00 now reads "IDU EEPROM malfunction".
• EL 0C: now reads "system lacks refrigerant".
• FH CC: refrigerant sensor error.
• EH C1, EH C2, EH C3: the refrigerant sensor detects a leak, is out of range with a leak detected, or is out of range.
• EC C1: another indoor unit's refrigerant sensor detects a leak (multi-zone).
• PC 03: pressure protection, low or high. PC 04: compressor feedback protection.
• PC 0L: low ambient temperature protection.

Display codes that are not errors

The DIY Select manual lists several codes as normal: dF (defrost), Cl (Active Clean), FP (the 46.4°F heating feature), FC (forced cooling), AP (Wi-Fi setup mode) and CP (remote switched off). The current Advantage manual adds CL as a filter cleaning reminder and nF as a filter replacement reminder on some models.

MrCool DIY Gen 1 to 3 and earlier Advantage codes

Older units use single-letter codes. This table comes from MrCool's Generations 1 to 3 indoor code list. The earlier Advantage user manual (version V071420) uses the same codes, apart from the ones marked DIY only.

On the earlier Advantage, the operation lamp flashes to match: once for E0, twice for E1, up to seven times for EC. The timer lamp stays lit for the F codes and flashes for the P codes. Gen 1 to 3 multi-zone outdoor units have their own list on the same MrCool page, where, for example, E8 means the outdoor fan speed is out of control. Our E8 error code guide covers that fault in general terms.

MrCool Advantage Series codes

The current Advantage installation and owner's manual (September 2025, R-454B models) uses the same two-part codes as the DIY Select, from EH 00 to PC 0L, including the refrigerant sensor codes. Use the 4th Gen table above with the DIY Select changes. The older Advantage models with E, F and P codes are in the second table.

EL 01 or E1: the indoor and outdoor units are not talking

MrCool's EL 01 and E1 guide says the code usually means a communication problem, often a loose connection or faulty wiring. What you can do:

1. Turn the power off at the breaker. MrCool's guide leaves it off for 15 minutes before any checks.
2. Think back: MrCool asks whether there was a recent storm or power surge.
3. Look over the outside of the units for damage you can see without opening anything.
4. Turn the breaker back on and run the unit.

The rest of MrCool's procedure is voltage testing at the wiring terminals and checking the boards. That is work for a licensed HVAC technician. On a multi-zone system, MrCool notes that an error on every zone points to the outdoor unit, while an error on one zone points to that zone's wiring or board.

PC 0L or P3: too cold outside

This code is a protection, not a breakdown. MrCool's P3 and PC 0L guide says it usually appears when the outdoor temperature falls below -13°F (-25°C), and wind chill or moisture can trigger it a little above that. MrCool's PC 0L page says the code clears itself once it warms up. Until then, MrCool suggests another heat source.

If it is well above -13°F and the code stays, MrCool says to turn the power off at the breaker for 15 minutes and back on. If it still shows, check that ice, snow or debris is not covering the outdoor temperature sensor, a black wire in a clear tube on the back of the outdoor unit. Anything past that, such as removing the top cover to check the sensor plug, is for a technician.

EL 0C and the refrigerant leak codes

EL 0C, EC, EH C1, EH C2 and EC C1 all point to refrigerant. On the current R-454B Advantage units, the Advantage manual says a leak alarm stops the outdoor compressor at once and runs the indoor fan. On EH C1 or EH C2 the buzzer beeps for 5 to 6 minutes, and you can press any button on the remote to stop it.

There is no owner fix for a leak, and refrigerant work needs a certified technician. The same manual says the refrigerant sensor lasts 15 years and cannot be repaired. Only MrCool can replace it, with a sensor it specifies. If your unit is cooling poorly without a code, our guide to a heat pump that is not cooling covers other causes.

Which MrCool manuals this page covers

These codes come from MrCool's own documents, opened in October 2026:

• DIY E Star 4th Gen owner's manual, version 03-21-23, and the matching 4th Gen troubleshooting guide.
• DIY Select owner's manual, August 5, 2026 (DIYS wall-mounted air handlers and condensers, R-454B).
• Advantage user manual V071420 (earlier models) and the Advantage installation and owner's manual of September 19, 2025.
• MrCool's support pages for the Gen 1 to 5 code lists and the EL 01, P3 and PC 0L codes.

MrCool's Universal, ProDirect and central ducted lines have their own code lists, and this page does not cover them. If your code is not here, check the manual for your model at mrcool.com/documentation or call MrCool support at (270) 366-0457, the number on its support pages as of October 2026. For a Mitsubishi Electric unit, see our Mitsubishi mini split error codes.