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Error code reference

LG Hvac Error Code E561

Supply air (SA) fan motor error

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Supply air (SA) fan motor error — motor RPM is lower than 120 RPM for about 40 seconds.

First step from the service manual

Check if motor connector (CN74) is dislocated from PCB; if so, reconnect it.

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

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What E561 means on a LG hvac

The E561 error code on LG HVAC systems indicates a Supply Air (SA) fan motor fault triggered when the motor's rotational speed drops below 120 RPM for approximately 40 consecutive seconds. The supply air fan is responsible for circulating conditioned air through the ductwork and into the occupied space. When this motor fails to reach or maintain its minimum operational speed threshold, the system's control board detects the abnormal RPM reading and shuts down operation to prevent damage and ensure safe performance.

This fault is detected through feedback signals sent from the fan motor to the main PCB. The motor connector CN74 is the critical link between the motor and the control board. A loose, corroded, or fully disconnected CN74 connector will interrupt this signal path, causing the PCB to read zero or near-zero RPM even if the motor itself is mechanically intact. This makes connector verification the logical and highest-priority first diagnostic step before any component replacement is attempted.

Beyond connector issues, true motor failures can stem from winding damage, bearing seizure, or capacitor failure causing the motor to draw excessive current without producing adequate rotation. Obstructions in the fan housing or a seized fan wheel can also mechanically prevent the motor from spinning up to speed, producing the same sub-120 RPM condition. Wiring faults between CN74 and the motor terminals should also be inspected for continuity if the connector is found properly seated.

Source: manufacturer service documentation.

Common causes of E561

  1. 01

    Disconnected or loose CN74 motor connector

    Wiring / connection

    The CN74 connector links the supply air fan motor to the main PCB. If this connector is dislodged, corroded, or poorly seated, the board cannot receive RPM feedback and will trigger E561. Inspect and firmly reseat the connector as the first step.

  2. 02

    Failed or seized fan motor bearings

    Part replacement

    Worn or seized bearings prevent the motor shaft from rotating freely, causing RPM to fall below the 120 RPM threshold. Listen for grinding or squealing noise prior to shutdown, and check whether the fan wheel spins freely by hand with power off.

  3. 03

    Blocked or jammed fan wheel

    Wiring / connection

    Debris, accumulated dirt, or a foreign object lodged in the fan housing can mechanically restrict the fan wheel from spinning at operational speed. Inspect the fan housing and wheel for obstructions and clean as needed.

  4. 04

    Damaged motor wiring harness

    Part replacement

    Breaks, shorts, or high-resistance faults in the wiring between the CN74 connector and the motor terminals can disrupt control signals and power delivery to the motor. Inspect the harness for visible damage and test continuity across each conductor.

  5. 05

    Defective supply air fan motor

    Part replacement

    Internal winding damage or a failed motor capacitor can prevent the motor from generating sufficient torque to reach 120 RPM. If wiring and connectors check out, motor resistance values and capacitor condition should be tested before replacement.

See the test procedure for each cause

Frequently asked questions about E561

What does E561 mean on a LG hvac?
E561 indicates a Supply Air fan motor error. Specifically, the system has detected that the SA fan motor RPM dropped below 120 RPM for approximately 40 seconds. The unit shuts down to prevent damage, and the fault is logged to alert a technician that the fan motor or its associated wiring and connectors need to be inspected.
How do I fix the E561 error on my LG HVAC unit?
Start by checking whether the motor connector CN74 has become disconnected or loose from the PCB, as this is the most common and simplest cause. If the connector is secure, further diagnosis should include inspecting the fan wheel for obstructions, testing the wiring harness for continuity, and evaluating the motor itself for bearing or winding failure. More involved repairs such as motor replacement should be performed by a qualified HVAC technician.
Is it safe to keep running my LG HVAC system when E561 is displayed?
No, the system will typically shut itself down when E561 is triggered, and you should not attempt to override this protection. Operating the unit with a non-functioning supply air fan can cause the heat exchanger or evaporator coil to overheat or freeze, potentially leading to more extensive and costly damage. Leave the unit off until the fault is diagnosed and repaired.
Will resetting my LG HVAC unit clear the E561 error code?
A power reset may temporarily clear the error display, but the code will return if the underlying cause has not been corrected. If the fan motor is mechanically seized, the connector is loose, or the wiring is damaged, the condition that triggered E561 will persist and the fault will reappear within 40 seconds of the motor failing to reach 120 RPM. Always address the root cause before assuming the error is resolved.
How much does it cost to repair an LG HVAC E561 fan motor error?
Repair costs vary depending on the cause. If the fix is simply reseating the CN74 connector, a service call fee in the range of $75 to $150 may be the only cost. If the supply air fan motor requires replacement, total costs including parts and labor typically range from $200 to $600 or more depending on the unit model and local labor rates. Getting a diagnostic quote from a certified technician before authorizing parts replacement is advisable.

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