DIY HVAC Tools

MRCOOL mini split code LL

Remote or wired controller locked.

  • TypeStatus, not a fault
  • SystemDisplay
  • Can I fix it?Usually a homeowner fix
  • Applies toindoor unit display (four-character codes)

What LL means on a MRCOOL

The controller lock is on: button presses are ignored until it is turned off. Not a fault.

On this platform, LL is a status, not a fault: the unit is telling you what it is doing; nothing is wrong.

What to do

You can almost always clear this yourself with the steps below.

  1. See your remote's manual for the lock combination; on many Midea-built remotes it is holding the up and down arrows together.

When to call a technician

This is not a fault. No technician is needed unless it will not clear.

Which MRCOOL units show LL

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 LL as "Remote or wired controller locked", 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 LL:

dFDefrost cycle runningCLFilter cleaning reminderAPWi-Fi pairing (access point) modeFPLow-temperature heating hold (46°F freeze-protection mode)FCForced cooling test modecFAnti-cold-air (heating warm-up)CPRemote on/off contact open
E0Indoor unit EEPROM parameter error / Outdoor unit EEPROM parameter error (outdoor display)E1Communication error between indoor and outdoor unitsE2Zero-crossing signal detection error / Communication error between the outdoor unit and the indoor units (outdoor display)E3Indoor fan speed out of control (indoor fan motor fault) / Communication error between outdoor main board and IPM board (outdoor display)E4Indoor room temperature sensor (T1) open or short circuit / Outdoor temperature sensor fault: coil (T3), ambient (T4), discharge (T5) or a zone coil outlet (T2B)E5Evaporator coil temperature sensor (T2) open or short circuit / Over-voltage or under-voltage protection (outdoor display)ECRefrigerant leak detected (low refrigerant charge)F0Overload current protection (compressor over-current)

All MRCOOL error codes

LL on other brands

The same characters do not always mean the same thing. Check the brand on your unit.

Questions people ask

Is LL on a MRCOOL mini split an error?

No. LL is a status message: remote or wired controller locked. The controller lock is on: button presses are ignored until it is turned off.

Do I need a technician for MRCOOL LL?

You can almost always clear this yourself with the steps below. This is not a fault. No technician is needed unless it will not clear.

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.