MRCOOL® Mini-Split Error Code & DIY Troubleshooting Guide
Seeing a strange code? Don’t panic—many MRCOOL® mini-split alerts are normal or easy to fix. Open a section below to see what the code means and what you can try before calling a pro.
🟢 Normal Operation Codes (No Fix Needed)
| Code | Meaning | What to Do |
|---|---|---|
| F | Defrost | Normal—unit is defrosting the outdoor coil. Wait. |
| CL | Active Clean | Self-cleaning mode; allow 20–30 minutes to complete. |
| FP | Freeze Protection | Automatic low-heat anti-freeze mode. Normal behavior. |
| FC | Forced Cooling | Factory/service mode. Power cycle to exit. |
| AP | WiFi AP Mode | Finish pairing in app, or press “LED” on remote 7× to exit. |
| CP | Remote Off | Power on again with the remote. |
🟠 Indoor Unit (IDU) Error Codes
| Code | Issue | Quick Fixes |
|---|---|---|
| EH 00 / EH 0A | EEPROM Failure | Breaker off 5 min → restart. If returns, board likely needs service. |
| EL 01 | IDU/ODU Communication | Check cables & connectors; reset indoor + outdoor units. |
| EH 02 | Zero-Cross Signal | Unplug/replug. Persistent? Call a technician (control board). |
| EH 03 | Fan Speed Error | Ensure vents clear; power cycle. May require fan motor. |
| EH 60 / EH 61 | Room/Pipe Sensor Fault | Reset; dust sensors. If returns, replace sensor(s). |
| EH 0 | Display Board Comm | Unplug; check display wiring; full reset. |
🔵 Outdoor Unit (ODU) Error Codes
| Code | Issue | Quick Fixes |
|---|---|---|
| EC 51 | EEPROM Error | Power reset. If returns, professional service required. |
| EC 52 / 53 / 54 / 56 | Sensor Errors (T3/T4/TP/T2B) | Clear leaves/snow/debris; power reset to clear code. |
| EC 07 | Fan Speed Out of Control | Confirm fan spins freely; reset breaker; call if jammed. |
🧊 Refrigerant & Sensor Codes
| Code | Issue | Quick Fixes |
|---|---|---|
| FH CC / EH C3 | Sensor Out of Range | Power reset. If it returns, sensor replacement may be needed. |
| EH C1 / EH C2 / EC C1 / EL 0C | Refrigerant Leak / Low Charge | Power off to protect compressor. Look for oily residue at lines; call a technician for leak test & recharge. |
⚙️ Compressor & Inverter Codes
| Code | Issue | Quick Fixes |
|---|---|---|
| PC 00 / 02 / 03 / 04 | Overload, IPM, Pressure, Drive | Breaker off 10 min; clean outdoor coils. If returns, call service. |
| PC 0L | Low Ambient Lockout | Normal protection in very cold weather. Use supplemental heat. |
🔴 Multi-Zone Mode Conflicts
| Code | Issue | Quick Fixes |
|---|---|---|
| LP | Conflicting Modes | Set all indoor units to the same mode (all heat or all cool). |
🧰 General Troubleshooting Tips
- Power reset: Turn off the breaker 5–10 minutes, then restart.
- Clean filters: Rinse every 2–4 weeks—clogs cause many issues.
- Clear airflow: Keep indoor vents and outdoor coils unobstructed.
- Remote batteries: Replace weak batteries.
- WiFi AP exit: Press “LED” on the remote 7× to exit pairing mode.
📞 When to Call a Professional
- Repeated EEPROM/sensor codes after power resets.
- Visible refrigerant leaks or oily residue near copper lines.
- Persistent ice buildup or no power after breaker checks.
- If you’re unsure about electrical or control board work.
Need Parts or Components? We’ve Got ’Em.
From sensors and control boards to pre-charged Quick Connect® line sets, remotes, filters, drain kits, and line-set covers—we stock genuine MRCOOL® parts and compatible accessories. No professional license required to purchase.
- Genuine MRCOOL replacement parts & DIY accessories
- Fast, FREE nationwide LTL shipping on qualifying orders
- U.S. support for product selection & install questions
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