Mitsubishi Electric mini split error code E1
Remote controller control board fault.
- TypeFault
- SystemControl board
- Can I fix it?Homeowner checks, then maybe a tech
What E1 means on a Mitsubishi Electric
The wired remote controller's own board failed its self-check.
On this platform, E1 is a fault: something has failed or is disconnected and needs diagnosis.
Common causes
- A failed controller.
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.
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
Controller replacement.
Which Mitsubishi Electric units show E1
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 E1 as "Remote controller control board fault", 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 E1:
E1 on other brands
The same characters do not always mean the same thing. Check the brand on your unit.
- Pioneer E1 Communication error between indoor and outdoor units
- Blueridge E1 High pressure protection / Communication error between indoor and outdoor units
- Gree E1 High pressure protection
- Zone Air E1 Indoor room temperature sensor fault (open or short circuit)
- Daikin E1 Outdoor unit control board (PCB) failure
- Trane E1 Indoor room temperature sensor fault (open or short circuit) / Remote controller control board fault
- Heil E1 Communication error between indoor and outdoor units / High pressure protection
- ACiQ E1 Communication error between indoor and outdoor units / Indoor room temperature sensor fault (open or short circuit)
Questions people ask
Can I reset a Mitsubishi Electric E1 code myself?
Yes. Turn the system off at the breaker for five minutes, then restart it. If E1 comes back, the fault is real and needs the checks above.
Is it safe to keep running a Mitsubishi Electric showing E1?
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 E1?
Work through the checks below first; they resolve most cases. If they do not, the repair itself may need a technician. Controller replacement.
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.