What it means
The installation manuals group E0 to E5 as "Communication failure between main remote controller and FTC". The service manual splits them: E0 and E4 are reception errors, E3 and E5 are transmission errors, and E1 and E2 are faults on the controller's own circuit board.
What to check, in order
- Switch off and on again
Mitsubishi's service manual has the engineer switch the indoor and outdoor units off and on again. Use the main switches only, and switch back on straight away so frost protection keeps working.
- Write the code down if it returns
Make a note of the code and contact your installer, as Mitsubishi's operation manual advises.
When to call your installer
Call your installer. Mitsubishi lists a loose or damaged controller cable, wiring outside the length and cable limits, more than one controller connected, electrical noise, or a fault on the FTC board or the controller's board. For E1 and E2 the fix is replacing the controller's board.
Quick answers
What does the Mitsubishi Ecodan E0-E5 error code mean?
The main remote controller and the indoor unit's control board (the FTC) have stopped exchanging data properly. The installation manuals group E0 to E5 as "Communication failure between main remote controller and FTC". The service manual splits them: E0 and E4 are reception errors, E3 and E5 are transmission errors, and E1 and E2 are faults on the controller's own circuit board.
Can I fix Mitsubishi Ecodan E0-E5 myself?
Easy (about 10 minutes). Start with: switch off and on again; write the code down if it returns. Call your installer. Mitsubishi lists a loose or damaged controller cable, wiring outside the length and cable limits, more than one controller connected, electrical noise, or a fault on the FTC board or the controller's board. For E1 and E2 the fix is replacing the controller's board.
Is Mitsubishi Ecodan E0-E5 worth repairing?
Worth fixing. Mitsubishi's first check is the cable between the controller and the indoor unit. If the controller itself has failed, it needs replacing.
Checked against
- Ecodan FTC5 Hydrobox Installation Manual, EHS(D)(C)-MEC / EHPX-VM2C (RG79D954H05) (PDF)
- Ecodan Hydrobox EHSC/EHSD series (D models) Installation Manual, error code table (manualslib copy)
- Ecodan Hydrobox EHSD/ERSD series (E models) Installation Manual DG79T728H01, error code table (manualslib copy)
- Ecodan Cylinder Unit Service Manual OCH714A, EHST/ERST/EHPT D models (PDF)
- Ecodan EHPT(15-17-21-25-30)X-UKH(L)EW1(S-L) Operation Manual, FTC7 (758753) (PDF)
Last reviewed October 2026. Manufacturers update their pages, and your manual is the final word. Spotted a mistake? Email contact@appliance-error-codes.com.