Error code reference

Daikin Air Conditioner Error Code U9

Signal transmission error between indoor unit and outdoor unit in the same system.

SourceDaikin Air Conditioner - Service Manual: RMXS-L Series Multi-Splitp. 256

Daikin codes Daikin air conditioner codes

Diagnostic procedure

The full U9 procedure

Step 1 is visible so you can confirm you are on the right page. The remaining steps, the ones that tell you whether to actually replace a part, unlock with any pass.

MyPros+ · DiagnosticsStep 1 preview

First diagnostic step

Wait 2 minutes and re-diagnose; then check other indoor units for UA, A1, A9, or U4 errors.

SourceDaikin Air Conditioner - Service Manual: RMXS-L Series Multi-Splitp. 256

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More steps, wiring diagram references, and verified part numbers

Includes expected resistance and voltage values, connector pinouts, and supersession notes for replacement parts.

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Where this code is documented

1 manual in the MyPros+ library documents this code for Daikin air conditioner.

Models covered by the manuals that document this code

More models are covered than are listed here.

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The full U9 procedure

Where this code is documented

Models covered by the manuals that document this code

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