Mitsubishi Electric mini split error code E3
Remote controller signal transmitting error.
- TypeFault
- SystemCommunication
- Can I fix it?Homeowner checks, then maybe a tech
What E3 means on a Mitsubishi Electric
The wired remote controller cannot send data to the indoor unit.
On this platform, E3 is a fault: something has failed or is disconnected and needs diagnosis.
Common causes
- A loose or damaged controller cable.
- Two controllers both set as main.
- A failed controller or indoor board.
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.
- Reseat the controller cable at both ends.
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
Technician check.
Which Mitsubishi Electric units show E3
This page applies to Mitsubishi Electric M-Series (MSZ), Mr. Slim (PKA/PCA), Hyper-Heating H2i and MXZ multi-zone units. Mitsubishi Electric's own documentation lists E3 as "Remote controller signal transmitting error", the same definition used across the Mitsubishi Electric 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 Mitsubishi Electric shows this code
Wall units without a wired controller signal a fault by blinking the operation indicator lamp; the code itself shows on a wired controller (MHK/PAR series) or on the wireless remote after entering its check mode (see your manual). On the outdoor unit, the control board LEDs blink the same code. P codes are indoor-unit faults, E codes are communication faults, F codes are outdoor-unit faults and U codes are outdoor-unit and compressor faults.
Other Mitsubishi Electric codes
Same part of the system as E3:
E3 on other brands
The same characters do not always mean the same thing. Check the brand on your unit.
- Pioneer E3 Indoor fan speed out of control (indoor fan motor fault) / Communication error between outdoor main board and IPM board (outdoor display)
- Blueridge E3 Low pressure protection (refrigerant shortage or blockage) / Indoor fan speed out of control (indoor fan motor fault)
- Gree E3 Low pressure protection (refrigerant shortage or blockage)
- Zone Air E3 Outdoor fan coil (condenser) temperature sensor fault (open or short circuit)
- Daikin E3 High pressure protection (high-pressure switch)
- Carrier E3 Indoor fan speed out of control (indoor fan motor fault)
- Trane E3 Outdoor fan coil (condenser) temperature sensor fault (open or short circuit) / Remote controller signal transmitting error
- Heil E3 Indoor fan speed out of control (indoor fan motor fault) / Low pressure protection (refrigerant shortage or blockage)
- ACiQ E3 Indoor fan speed out of control (indoor fan motor fault) / Outdoor fan coil (condenser) temperature sensor fault (open or short circuit)
Questions people ask
Can I reset a Mitsubishi Electric E3 code myself?
Yes. Turn the system off at the breaker for five minutes, then restart it. If E3 comes back, the fault is real and needs the checks above.
Is it safe to keep running a Mitsubishi Electric showing E3?
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 Mitsubishi Electric E3?
Work through the checks below first; they resolve most cases. If they do not, the repair itself may need a technician. Technician check.
Sources
- Mitsubishi Electric M-Series and Mr. Slim service manuals (self-diagnosis tables)
Updated September 2026. Codes and definitions vary by model year. If your manual disagrees with this page, your manual wins. Send a correction.