The short answer
MrCool, Pioneer, Gree and Senville mini splits all show letter codes, but the same letters don’t mean the same thing from brand to brand. H1 is a normal defrost on a Gree and a high pressure fault on a Pioneer. On a MrCool, the code is two letters and two characters, like EL 01 for a communication fault or EL 0C for low refrigerant. Find your brand’s table, and if you’re in Northern Virginia and the code won’t clear, call before you start taking a DIY system apart.
Check the label first
These brands share a lot of parts and look alike on the wall. The brand and model number are on the label on the side of the indoor head. Read it before you read any chart, because a code from the wrong brand’s list will send you in the wrong direction.
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MrCool codes (5th generation DIY)
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| Code | What it means |
|---|---|
| EH 00, EH 0A | The indoor board’s memory |
| EL 01 | The indoor and outdoor units aren’t talking. On a DIY install, check the wire between them with the power off |
| EH 02 | The zero crossing signal on the indoor board |
| EH 03 | Indoor fan speed |
| EH 60, EH 61 | Room sensor, indoor coil sensor |
| EH 0b | The main board and the display board aren’t talking |
| EC 07 | Outdoor fan speed |
| EH C1, EH C2 | The refrigerant sensor detected a leak |
| EH C3 | The refrigerant sensor is out of range |
| EL 0C | Low refrigerant |
| PC 00, PC 08 | The power module (IPM), or over current |
| PC 01 | Voltage too high or too low |
| PC 02, PC 06 | The compressor top or discharge is too hot |
| PC 03 | Pressure protection |
| PC 04 | The compressor drive |
| PC 0A | The outdoor coil is too hot. Clear leaves and debris |
| PC 0F | The PFC module |
| PC 0L | Low outdoor temperature protection |
Senville’s AURA series uses the same EH, EL, EC and PC families, so most of that table carries over. Check Senville’s own chart for your model.
If a MrCool shows EH C1 or EH C2: the system’s R-454B sensor found refrigerant in the room. Open windows, turn the system off at the breaker, keep flames and sparks away, and call. Don’t turn it back on to test it. Why newer systems carry that sensor is in the R-454B change.
DIY install notes from MrCool’s manual
- The Quick Connect line set fittings go on once. Taking them apart and reconnecting can break the seal and void the warranty.
- No Teflon tape on the fittings. Check each joint for leaks with soapy water.
- The drain hose has to slope down with no loops or kinks, and its end can’t sit in water.
- After a power cut or a mode change, expect about a 3 minute delay before it restarts.
The warranty terms, the electrical work and the line set rules are in our DIY mini split guide.
Pioneer codes (Diamante and Quantum)
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| Code | What it means |
|---|---|
| E0 | The indoor and outdoor units aren’t talking |
| E1, E2, E3 | Room sensor, indoor coil sensor, outdoor coil sensor |
| E4 | Refrigerant shortage or a system fault. On a new install, check both service valves are fully open |
| E6, EF | Indoor fan, outdoor fan |
| E9 | The power module or compressor drive |
| d4 | The drain pan is full |
| F8 | The reversing valve |
| Fy, Hd | Refrigerant shortage, refrigerant leak protection |
| H1, H2 | High pressure switch, low pressure switch |
| P1, P2 | Voltage too high or too low, over current |
| P8 | Outdoor temperature too high or too low |
| PA | Heads set to different modes |
Gree codes
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| Code | What it means |
|---|---|
| E1 | High pressure protection |
| E2 | Anti-freeze protection on the indoor coil |
| E3 | Low pressure, or a blockage |
| E4 | The compressor discharge is too hot |
| E5 | Over current or voltage protection |
| E6 | The indoor and outdoor units aren’t talking. It’s the most common Gree code, usually the wire between the units |
| E7 | Heads set to different modes |
| F0 | Refrigerant leak or low charge |
| H6 | No signal back from the indoor fan |
| U7 | The reversing valve |
The normal ones
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| Display | Brand | What it means |
|---|---|---|
| dF | MrCool, Pioneer | Defrost |
| H1 | Gree | Defrost (on a Pioneer it’s a high pressure fault) |
| FP | MrCool | Freeze protection: holds the room at 46°F while you’re away |
| CL | Pioneer | Time to clean the filters |
Cold air prevention is normal on all of them: the head waits until its coil is warm before it blows, anywhere from 1 to 10 minutes. Heat range varies too. A 5th generation MrCool heats down to -13°F, and Pioneer’s Diamante heats from 5°F to 86°F outside. More in mini split not heating.
One reset, not ten. Turn the head off with the remote, switch the breaker off for about 5 minutes, then turn it back on. If the same code comes back, write it down with the model number from the label and call. Resetting a fault over and over can hide what it was protecting.
Brand by brand: Mitsubishi, Carrier, Daikin, Fujitsu, LG and Samsung. Every code family we’ve written up is on our error codes and warning lights page.
Book it
A mini split visit starts with our $99 diagnostic, and you get the repair price in writing before anything is opened. Call (703) 997-9757 or book a visit online and tell us the brand and the code or what you’re seeing. Rated 5.0 stars across 1,138 reviews on Google, Angi, Yelp, the BBB and Facebook, Virginia Class A license 2705192276.
Mitsubishi Electric, Carrier, Daikin, Fujitsu, LG, Samsung, MrCool, Pioneer, Gree and Senville are trademarks of their owners.
Questions people ask
What does EL 01 mean on a MrCool mini split?
The indoor and outdoor units aren’t communicating. On a DIY install it’s usually the wire between them. Turn the power off before you check it.
What does EH C1 mean on a MrCool?
The R-454B refrigerant sensor detected a leak. Open windows, turn the system off at the breaker, keep flames and sparks away, and call.
What does E4 mean on a Pioneer mini split?
A refrigerant shortage or a system fault. On a new install, first make sure both service valves at the outdoor unit are fully open.
What does H1 mean on a Gree mini split?
Defrost, which is normal. On a Pioneer, H1 means the high pressure switch tripped, so check the brand first.
Can I reconnect a MrCool Quick Connect line set?
MrCool says the fittings go on once. Taking them apart and reconnecting can break the seal and void the warranty.
