A9Daikin · VRV IV RXTQ-TA / RXTQ-TB · Heat Pump

Daikin VRV IV RXTQ-TA / RXTQ-TB error code A9

Indoor unit electronic expansion valve abnormality

Needs attention soon

Also written as A9-01, A9-02, expansion valve, EEV, refrigerant leak

Which models this applies to. Indoor unit

Quick answer

On Daikin VRV IV RXTQ-TA / RXTQ-TB, A9 is a fault. It means indoor unit electronic expansion valve abnormality. A first thing to check: A failed electronic expansion valve coil.

Applies to: Daikin VRV IV RXTQ-TA / RXTQ-TB; Daikin VRV IV RXTQ heat pump codes · Heat Pump
Type of code: Fault; Urgency: Needs attention soon
First safe check: Check the connector at the electronic expansion valve coil, because the manual names a disconnected connector as a cause in its own right and it is far cheaper than a valve.

Checked 2026-09-26

What A9 means on this model

The indoor expansion valve is not metering refrigerant correctly, or refrigerant is escaping past it. Sub-code A9-01 is a valve or connector error and A9-02 is a refrigerant leak detection error, where Daikin states the valve leaks even when closed and directs replacing the valve. Dust clogging is listed as its own cause under this code.

Symptoms you will notice

Indoor unit shows A9 and stops
The unit cools or heats but weakly and slowly
The unit runs continuously without reaching setpoint
A slow leak that eventually takes out the whole system

Common causes

The code tells you what the control detected, not which part failed. These are the causes we see most often, roughly in order of likelihood:

A failed electronic expansion valve coil
A disconnected connector at the expansion valve
Dust and scale clogging the expansion valve, which the manual names as its own condition
A leaking expansion valve that passes refrigerant even when commanded closed
A refrigerant charge that has leaked down over time

What you can safely check

These are homeowner-level checks. None of them need you to open a live electrical compartment or work on gas.

Check the connector at the electronic expansion valve coil, because the manual names a disconnected connector as a cause in its own right and it is far cheaper than a valve.
Assess whether the indoor coil has been cleaned recently. A9 is a dust clogging code on this platform and a long unserviced coil is the most likely story.

Do not do these

×Do not solder or braze on the refrigerant circuit without recovering the charge and the factory procedures, which is licensed work.
×Do not swap the expansion valve for a leak that has not been found. The manual attributes A9-02 to a valve that leaks, but a leak elsewhere will come back as U0 refrigerant shortage.

When to call a technician

Book a technician, do not keep resetting it

This fault will not clear on its own. Every power cycle gives the control one more failed attempt, and repeated attempts are what turn a cheap part replacement into a seized or contaminated system.

The refrigerant circuit is sealed and legally requires licensed handling. Opening it without certification releases refrigerant and can put the whole system in violation of regulation, so a low-pressure or high-pressure fault on this equipment is a call-out, not a weekend job.
If the appliance has stopped mid-cycle, is making a noise you have not heard before, or smells burnt, stop reading here and call. Those are symptoms of something the fault code does not describe well enough.

A licensed technician job. There is no homeowner step here beyond noticing the code.

What it costs to fix

Parts

Electronic expansion valve $150 to $400 plus coil $40 to $120.

Labor

Two to four hours including refrigerant recovery and recharge.

DIY or technician