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Error code reference

Samsung Washer Error Code LO

Door unlock fail error

Samsung codesSamsung washer codes

Door unlock fail error — door lock switch terminal connected incorrectly, broken terminal, intermittent electric wire leakage, or main PCB fault.

First step from the service manual

In door unlock state, check motor resistance and door unlock contact resistance.

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

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What LO means on a Samsung washer

The LO error code on a Samsung washer indicates a door unlock failure. This means the machine attempted to release the door lock mechanism at the end of a cycle but was unable to confirm a successful unlock. The door lock system relies on a lock motor and a set of contact switches that communicate the lock and unlock positions back to the main PCB. When the control board commands the door to unlock and the expected feedback signal is not received within the required timeframe, the LO code is triggered.

The most critical first diagnostic step is to check the door lock motor resistance and the door unlock contact resistance while the door is in the unlocked state. A faulty motor winding, a broken terminal connection at the lock assembly, or a wiring harness with intermittent leakage can all produce incorrect resistance readings and prevent proper feedback to the control board. Terminal connections at the door lock switch are a common point of failure due to vibration and repeated thermal cycling during normal use.

If wiring and terminal integrity check out within specification, the fault may lie in the main PCB itself. A damaged or degraded PCB can fail to correctly send the unlock command voltage or fail to read the returning signal from the door lock contacts. Diagnosing a PCB fault typically involves ruling out all wiring and mechanical lock component issues first, since replacing the control board is the most involved and costly repair path for this error.

Source: manufacturer service documentation.

Common causes of LO

  1. 01

    Broken or improperly connected door lock terminal

    Wiring / connection

    The wiring terminals at the door lock switch connector can become loose, corroded, or broken from repeated use and vibration. Visually inspect the connector pins and check for continuity at the terminal.

  2. 02

    Faulty door lock motor

    Part replacement

    The lock motor that physically drives the locking mechanism can fail internally, producing out-of-spec resistance readings when measured in the unlocked state. A motor with incorrect resistance will not operate reliably and must be replaced as part of the door lock assembly.

  3. 03

    Intermittent electric wire leakage

    Part replacement

    Damaged or pinched wiring in the harness between the door lock assembly and the main PCB can cause intermittent shorts or leakage current. Flex the harness while checking resistance to identify any breaks or insulation failures.

  4. 04

    Faulty door unlock contact switch

    Part replacement

    The contact switch that signals the unlocked position to the control board may be worn or damaged, sending no signal or an incorrect resistance reading even when the door is physically unlocked.

  5. 05

    Main PCB fault

    Part replacement

    If all wiring, terminals, and door lock components test within normal resistance ranges, the main PCB may be failing to send the proper unlock command voltage or to read the feedback signal correctly. This is typically diagnosed by exclusion after other components pass testing.

See the test procedure for each cause

Frequently asked questions about LO

What does LO mean on a Samsung washer?
The LO code on a Samsung washer stands for door unlock failure. It means the washer attempted to unlock the door, typically at the end of a cycle, but the control board did not receive confirmation that the unlock was successful. The cause can range from a loose terminal or broken wire at the door lock assembly to a faulty lock motor or main PCB issue.
Can I fix the LO error on my Samsung washer myself?
Some causes of the LO error are accessible to a DIY repair. Checking and reseating the wiring terminals at the door lock switch connector is a reasonable first step that requires no special tools. If the lock motor or contact switch needs replacement, those parts can often be sourced and swapped by someone comfortable with appliance repair. A main PCB fault is a more complex repair and may be better handled by a technician.
Is it safe to use my Samsung washer when the LO error is showing?
It is not recommended to continue running the washer while the LO code is active. The error indicates the door lock system is not functioning correctly, and the machine may keep the door locked or fail to lock it reliably during a cycle. Running the washer with an unreliable door lock could pose a water leak or safety risk.
How much does it cost to repair a Samsung washer LO error?
Repair costs vary depending on the root cause. Replacing a door lock assembly typically runs in the range of $80 to $180 for parts and labor combined. If the main PCB is at fault, the cost is higher, generally in the range of $200 to $400 or more depending on the specific model and service rates in your area.
Will resetting my Samsung washer clear the LO error code?
A power reset, such as unplugging the washer for a few minutes and restarting it, may temporarily clear the LO code if the fault was caused by a momentary signal issue. However, if there is an underlying problem with the door lock terminal, motor, wiring, or PCB, the error will return. A reset alone does not fix the mechanical or electrical fault causing the code.

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