Indoor and Outdoor Unit Communication Error
What it means
This code appears on Haier split air conditioners when the indoor board loses communication with the outdoor board, so the outdoor unit stops and there is no cooling. Haier codes differ between series, so confirm the meaning in your unit manual before buying any part. The same code can mean something else on other brands.
Models covered: Haier split air conditioners; codes differ between Haier series, so confirm with the unit manual.
Symptoms3
- The outdoor unit does not run.
- The indoor fan runs but the air is not cold.
- The code shows immediately or a few minutes after start.
Possible causes5
- Loose or corroded interconnecting cable terminals in either unit.
- Wrong wire order after installation or relocation.
- Cable damaged by sun or rodents, or an exposed joint.
- No power reaching the outdoor unit or a blown fuse on its board.
- Faulty outdoor or indoor board.
How to diagnose5
- Confirm the code meaning in your unit manual.
- Switch off at the breaker for a few minutes, then restart.
- The technician matches the wire order to the unit diagram and tightens the terminals.
- The technician measures voltage at the outdoor unit and checks its board fuse.
- The technician tests the cable, then identifies the faulty board.
How to fix5
- Tighten and clean the terminals and correct the order.
- Replace the damaged cable.
- Replace the fuse after finding why it blew.
- Replace the faulty outdoor or indoor board.
- Run the unit and confirm the outdoor unit keeps running without the code.
Repair cost
In Saudi riyals; the highlighted part is the expected range for this fault.
In the Saudi market: SAR 100–2,500 (≈ USD 27–667)
Our prices come from the Saudi market, converted at a fixed rate (SAR 3.75 per USD). Prices in your country may differ a lot, so we show the cost level.
Terminal or cable repair is low cost; the outdoor inverter board is the top of the range.
Prices are rough estimates including the part and the technician’s fee, and vary with brand, model and part source.
Prices last updated: September 2026
Frequently asked questions
Should I start by replacing the board?
No. Start with the cable, terminals and power at the outdoor unit, which cause most cases.
Does E7 mean the same on every Haier unit?
On many series yes, but codes differ between series, so check your unit manual.
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