Indoor PCB Defect

What it means

This code appears on Daikin split, ducted and cassette air conditioners and means the indoor unit's control board (PCB) has detected a fault in itself, such as a memory or processor error. The unit usually stops completely until the cause is fixed. The same code can mean something else on other brands.

Models covered: Daikin split air conditioners and Daikin ducted/cassette (SkyAir) units, which share the same error code system; the code shows on the wired remote or via the wireless remote check function.

Related codes: U4E1A6A3

Symptoms4

• The unit stops and A1 shows on the remote controller or in the wireless remote check.
• The operation lamp on the indoor unit blinks and neither the fan nor cooling starts.
• The unit may run after a power reset, then the code returns minutes or hours later.
• Sometimes the unit does not respond to the remote at all.

Possible causes5

• A temporary board error after a sudden power cut or a voltage fluctuation.
• A failed indoor PCB damaged by moisture, heat or a voltage surge.
• A loose or corroded connector on the board, such as the remote or sensor connectors.
• A settings error or a faulty settings chip on the board on some models.
• Water or insects inside the indoor unit's electrical box.

How to diagnose5

1. Switch the unit off at the breaker for several minutes, restart it and watch whether the code returns.
2. Check that the supply voltage in the home is stable, especially at summer peak hours.
3. With the power off, a technician opens the indoor electrical box and inspects the board for burn marks, moisture or corrosion.
4. The technician checks that every connector on the board is secure and that the settings chip, where fitted, is intact.
5. If the code persists after the wiring and supply are confirmed good, the board is judged faulty per the Daikin service manual.

How to fix5

1. Restart the unit after switching off the breaker for several minutes; if the code never returns, a brief power glitch was the likely cause.
2. Fit a voltage protector if the local supply is unstable.
3. Clean and reseat the connectors and repair any damaged wire.
4. Replace the indoor PCB with a genuine part that matches the model, transferring the settings or chip as Daikin instructs.
5. Run the unit in cooling and confirm the code does not return.

Repair cost

In Saudi riyals; the highlighted part is the expected range for this fault.

The cost stays low when a reset or a connector repair solves it, and rises when a genuine replacement board is needed, since its price depends on the model and dealer availability.

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