Gree Mini Split Error Code E6: Indoor and Outdoor Unit Communication Error (Meaning, Causes, Fixes)
What the code means
Gree's service manuals list E6 as a communication malfunction (communication error) between the indoor and outdoor unit. When it happens in cooling, fan or dry mode the compressor and outdoor fan stop while the indoor fan keeps running, and in heating the whole unit stops. On Gree single-zone systems the cable between the units uses terminals 1, 2 and 3 plus ground: 1 and 3 carry power and terminal 2 is the communication wire. Gree's guide adds a useful timing clue: if E6 shows the moment the system powers on, start with the indoor unit; if it appears about 3 to 4 minutes after power-up, look at the outdoor unit first.
Likely causes
- The wrong cable or a splice in the run between the units. Gree's E6 guide calls this the number one culprit and specifies 14-gauge, 4-conductor stranded 600 V wire, grounded, with good crimps and no breaks or splices.
- Loose, swapped or damaged wires at the 1, 2, 3 and ground terminals, or damaged wiring inside the indoor or outdoor unit, which Gree's service manuals check first.
- A miswired accessory in the line, such as a condensate pump, float switch or disconnect, which Gree says can interrupt communication.
- A grounded or shorted component, such as a failing indoor fan motor, dragging down the communication voltage.
- A damaged communication circuit on the outdoor main board (AP1) or the indoor main board, or on some models an indoor board that doesn't match the display board or outdoor board.
Safe DIY checks
The cable between a Gree indoor and outdoor unit carries line voltage on terminals 1 and 3, and the communication wire itself carries about 55 V DC, so turn off the breaker or disconnect before touching any wiring. Inverter outdoor units can hold a dangerous charge for a while after power is removed, so leave the covers on and let a qualified technician do the voltage tests and board work.
- Turn the system off at the breaker or outdoor disconnect, wait a few minutes, and turn it back on. Note whether E6 appears right away or after 3 to 4 minutes, since Gree uses that timing to point to the indoor or outdoor unit.
- Ask yourself what changed. If the system worked fine before, Gree's flowcharts look for damaged wiring; if it never worked right after installation, they start with a wiring mistake, so call the installer.
- With the power off, look along the visible part of the cable between the units for cuts, chewed insulation, crushed spots or tape-wrapped splices. Gree says to inspect the whole run, not just the ends.
- If a condensate pump, float switch or extra disconnect was added, check that it was installed by a qualified person and that the code started after that work; tell your technician.
- Leave the terminal covers and electrical boxes closed. The terminals carry line voltage, so the meter tests below are a job for a technician.
🛠 When to call a pro
- Check that the 1, 2, 3 and ground connections match at both units, per the wiring diagram, and that the cable is the specified 14-gauge, 4-wire stranded type with no splices.
- With power on, measure AC across terminals 1 and 3 and a fluctuating DC voltage between 1 and 2. Gree's guide says that with wire 2 removed there should be about 53 to 57 V DC from 1 to 2 and from 2 to ground at the outdoor board, and the same at the indoor board; an unstable reading points to a board fuse or component fault. Use the model's service manual chart for exact values on 115 V or 230 V units.
- With power off, ohm out the communication wire, or run a temporary cable to see if the error clears.
- Use Gree's single-zone service tool (part GREGT2A3AD), which can stand in for the indoor unit to test the outdoor unit and the other way around. If both units run on their own, the fault is in the wiring between them.
- Check that the indoor fan runs in fan mode; if unplugging it changes E6 to a fan error, the motor is the likely problem. Only after the wiring and other components check out should the outdoor main board (AP1) or the indoor main board be replaced, per Gree's flowcharts.
Parts that commonly fix it
Always match the part number to your exact model.
Indoor/outdoor connecting cable
Gree specifies 14-gauge, 4-conductor stranded 600 V wire with no splices; a technician can run a temporary cable to test.
Search eBay →Outdoor main board
Replace only after the wiring and voltage tests point to the outdoor communication circuit; match the outdoor unit model number.
Search eBay →Multimeter
For a qualified technician's voltage and continuity checks on the communication wire.
Search eBay →Sources
- Gree Comfort tech tip: GREE Mini-Split E6 Error Code Troubleshooting (wrong wire or splice as top cause, 14 ga 4-wire stranded cable, startup vs 3-4 minute timing, GREGT2A3AD service tool steps, 53-57 V DC checks, accessories, fan test)
- Gree America 27 SEER Jasmine mini split service manual (E6 communication malfunction, unit status, two diagnosis flowcharts: connection wire, board matching, built-in wiring, outdoor AP1 and indoor AP2 boards)
- Gree GoCool service manual (E6 communication error of indoor and outdoor unit: causes and diagnosis flowchart)
- Gree console service manual (communication malfunction between indoor and outdoor unit: cool stops compressor with indoor fan running, heat stops all loads; check signal cable connection)
Last reviewed 2026-10-24. Always confirm against the manual for your exact model number.