Code: E9🔧 Daikin Mini Split

Daikin Error Code E9: Electronic Expansion Valve Coil Fault (Meaning, Causes, Fixes)

Reviewed 2026-10-24 · Based on 4 manufacturer & service sources

What the code means

Daikin's SkyAir inverter service manual SiUS25-501 titles E9 "Outdoor Unit: Malfunction of Moving Part of Electronic Expansion Valve." The outdoor board checks whether the expansion valve connector is plugged in and whether the valve coil has continuity, and it sets E9 when that check fails at power-on. Daikin's VRV IV service manual SiUS341615E calls the same code "Electronic Expansion Valve Coil Abnormality," set when no current flows through the coil's common wire when the power is turned on, and its sub-codes say which valve and which outdoor unit: for example E9-01 is expansion valve 2 (Y2E) on the master unit and E9-04 is expansion valve 1 (Y1E) on the master unit, while E9-20 to E9-25 mean a defective valve coil. Daikin's Simple Self-Diagnosis code list gives the same meaning across its equipment: "Malfunction of electronic expansion valve coil." E9 isn't in the error table for Daikin's Entra wall-mount mini splits, so check your model's manual if you see it on a wall-mount unit.

Likely causes

Safe DIY checks

⚠ Before you start

Turn off the power at the breaker or outdoor disconnect before opening any panel or unplugging connectors. Daikin warns that connecting or disconnecting connectors with power on can damage parts, and the outdoor inverter board can hold a dangerous charge after power is removed. Replacing the valve body itself means opening the refrigerant circuit, which in the US requires an EPA Section 608 certified technician.

  1. Turn the system off at the breaker or outdoor disconnect, wait a few minutes, then turn it back on and restart once. Daikin's own flowchart starts here: if the unit returns to normal, the code was likely caused by something outside the unit, such as electrical noise.
  2. Note the full code your controller shows, including any sub-code like E9-01 or E9-04 on VRV systems, since it tells the technician which valve to check.
  3. Look around the outdoor unit for recent damage, pests, or work that could have disturbed wiring, but leave the cover on.
  4. If E9 comes back after a power reset, stop and call a licensed HVAC technician. The fix means opening the outdoor unit and testing the valve coil and board.

🛠 When to call a pro

  • Following Daikin's SiUS25-501 flowchart: cycling power, then confirming the electronic expansion valve is connected to X26A and X28A on the outdoor PC board (A1P), reconnecting it and cycling power again if not.
  • Checking coil continuity with the valve unplugged from the board. On SkyAir units Daikin's table expects about 150 ohms between each coil pin and its common pin, about 300 ohms across paired coils, and no continuity on the other pairs.
  • On VRV IV systems (SiUS341615E), reading the E9 sub-code in monitor mode to find the valve (Y1E: E9-04 master, E9-07 slave 1, E9-10 slave 2; Y2E: E9-01 master, E9-05 slave 1, E9-08 slave 2), confirming the connector, and measuring pins 1 to 4 against pin 6, which should each read 40 to 50 ohms.
  • Replacing the electronic expansion valve (or its coil) if the resistance is out of range, or replacing the outdoor unit PC board (A1P) if the connector and coil both check out.

Parts that commonly fix it

Always match the part number to your exact model.

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Digital multimeter

For a technician checking the expansion valve coil resistance against Daikin's table.

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Electronic expansion valve coil

Only if the coil reads open or out of range; order by your outdoor unit model number.

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Outdoor control board

Daikin's last step when the connector and coil check out and E9 keeps returning; match it to your exact outdoor unit model.

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Sources

  1. Daikin SkyAir Inverter service manual SiUS25-501, 4.18 "E9" Outdoor Unit: Malfunction of Moving Part of Electronic Expansion Valve (pp. 116-117, flowchart and coil check table), Daikin Comfort
  2. Daikin VRV IV Heat Pump service manual SiUS341615E (RXYQ-TA), error code list (E9-01 to E9-25) and 3.34 Electronic Expansion Valve Coil Abnormality (pp. 226-227), Daikin Comfort
  3. Daikin Industries, Simple Self-Diagnosis by Malfunction Code (E9 malfunction of electronic expansion valve coil: disconnected connectors, defective valve coil, defective outdoor unit control PCB)
  4. Daikin Entra wall mount service manual FTK(X)B/RK(X)B AXVJU, 3.3 inverter error code table (no E9), Daikin Comfort

Last reviewed 2026-10-24. Always confirm against the manual for your exact model number.