mypros+
Error code reference

Samsung Air Conditioner Error Code Ax

Breakaway of xth indoor unit EVAP IN sensor (x = indoor unit address).

Samsung codesSamsung air conditioner codes

Breakaway of xth indoor unit EVAP IN sensor (x = indoor unit address).

First step from the service manual

Check breakaway of indoor unit EVAP IN sensor and reassemble to correct.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

MyPros+ Max

Get the full diagnostic procedure for Ax.

  • Step-by-step tests with expected resistance, voltage, and continuity values
  • Wiring diagram references and connector pinouts from the OEM service manual
  • Verified part numbers when replacement is required
Get the full procedure

$29/month · Cancel anytime · Or $9.95 3-day pass

What Ax means on a Samsung air conditioner

The Ax error code on a Samsung air conditioner indicates a disconnection or breakaway of the evaporator inlet (EVAP IN) temperature sensor on the xth indoor unit in a multi-unit system, where x corresponds to the specific indoor unit's address. This sensor is a thermistor mounted at the refrigerant inlet side of the indoor evaporator coil. It monitors incoming refrigerant temperature to help the system regulate cooling cycles, detect frost conditions, and manage overall system efficiency. When the control board loses a valid resistance signal from this sensor, it flags the Ax fault to identify which unit in the network is affected.

The term "breakaway" refers specifically to a physical disconnection of the sensor from its mounting position or connector, rather than an electrical failure within the sensor itself. The EVAP IN sensor is typically clipped or fitted into a bracket against the evaporator coil tubing. Vibration, improper servicing, or mechanical stress can cause the sensor to pull free from its clip, disrupting the thermal contact and signal integrity needed for accurate temperature measurement.

Because this is a multi-unit system, the address value x is critical for pinpointing which indoor unit requires attention. Technicians should identify the corresponding indoor unit by its address setting and physically inspect the sensor's mounting clip and wiring harness connection at that unit. The primary corrective action is to reseat the sensor firmly in its bracket and verify the connector is fully engaged before restarting the system.

Source: manufacturer service documentation.

Common causes of Ax

  1. 01

    Sensor dislodged from mounting clip

    Wiring / connection

    The EVAP IN sensor has physically pulled free from its bracket or clip on the evaporator coil tubing. This is the most common cause and is confirmed by visually inspecting the sensor position at the affected indoor unit.

  2. 02

    Loose or disconnected wiring harness connector

    Wiring / connection

    The connector joining the sensor lead to the indoor unit control board may have worked loose, breaking the electrical circuit. Check the connector at both the sensor end and the board end for a secure fit.

  3. 03

    Damaged sensor lead wire

    Part replacement

    The wire running from the sensor to the control board may be pinched, cut, or broken, preventing signal transmission. Inspect the wire routing for any visible damage or sharp bends.

  4. 04

    Failed EVAP IN thermistor

    Part replacement

    If the sensor has been dislodged repeatedly or exposed to moisture, the thermistor element itself may have failed. A resistance check at the sensor terminals will confirm whether the component is within the expected range.

  5. 05

    Incorrect indoor unit address assignment

    Wiring / connection

    If the unit address has been misconfigured, the system may report a sensor fault on the wrong unit or fail to locate the sensor signal entirely. Verify the address dip switch or setting on the affected indoor unit matches the system configuration.

See the test procedure for each cause

Frequently asked questions about Ax

What does Ax mean on a Samsung air conditioner?
The Ax error code indicates that the evaporator inlet temperature sensor on the xth indoor unit has become disconnected or has broken away from its mounting position. The x in the code represents the address of the specific indoor unit where the fault was detected. This sensor monitors incoming refrigerant temperature at the indoor coil, and the system cannot operate normally without a valid reading from it.
How do I fix the Ax error on my Samsung air conditioner?
Start by identifying the indoor unit with the address number matching x in the error code. Open the indoor unit's front panel and locate the EVAP IN sensor, which is clipped against the evaporator coil near the refrigerant inlet. Firmly reseat the sensor in its mounting clip and check that its wiring connector is fully plugged in. If the sensor lead or the sensor itself appears damaged, the component will need to be replaced before the error will clear.
Is it safe to keep running my air conditioner with the Ax error code?
It is not recommended to continue running the system with this error active. Without a functioning EVAP IN sensor, the indoor unit cannot accurately regulate the refrigerant cycle, which can lead to frost buildup on the evaporator coil or other operational issues. The system may restrict or disable the affected unit to protect itself until the fault is resolved.
Will resetting my Samsung air conditioner clear the Ax error code?
A simple reset will not permanently clear the Ax error if the underlying cause has not been corrected. The code will return as soon as the system powers up and attempts to read the disconnected or missing sensor. The sensor must be physically reseated or replaced, and the wiring connection verified, before the error will stay cleared.
How much does it cost to repair the Ax error code on a Samsung air conditioner?
If the fix is simply reseating a dislodged sensor, the cost is primarily a service call fee, typically in the range of $75 to $150 depending on your area. If the sensor wire is damaged or the thermistor has failed and needs replacement, total repair costs including parts and labor generally range from $100 to $250. Costs can be higher for multi-unit systems where accessing the specific indoor unit requires additional work.

Related Samsung air conditioner codes

All Samsung air conditioner codes
View all 572 Samsung air conditioner codes

78,000+ service manuals · 160,000+ error codes · 55+ brands

Get Started

$29/month · Cancel anytime · Or $9.95 3-day pass