Carrier error code E6
What it means
Communication error between indoor and outdoor units.
Possible causes
Interconnecting cable open or reversed Poor or corroded terminal connections Failed communication circuit on indoor or outdoor PCB
Suggested fix
Verify terminal mapping, cable continuity and connection quality, and confirm outdoor unit power; only if these are correct should you proceed to test and replace the faulty control board.
Safety first. Isolate the power supply before inspecting any unit. Refrigerant-circuit
and electrical repairs must be carried out by a qualified, registered technician.
Other Carrier codes
- E1 — High pressure protection in the refrigeration circuit.
- E2 — Evaporator coil temperature sensor fault.
- E3 — Low pressure protection.
- E4 — Compressor discharge temperature protection.
- E5 — Overcurrent or overload protection.
- EC — Refrigerant leak detection alarm.
- F0 — Low refrigerant protection.
- P0 — High voltage protection.
- P1 — Low voltage protection.
- P4 — Fan speed fault.