Samsung Washer Diagnostic Mode: How to Enter It & Read Stored Codes
Samsung washer service modes are model-specific by design — the entry combination and test steps live in each model's tech sheet, and Samsung doesn't publish one universal sequence. This page tells you what the mode does, the entry patterns Samsung platforms use, where your tech sheet hides, and how to make the results useful (including Samsung's Smart Check feature on app-connected models).
What the mode gives you
A Samsung service/test mode typically offers: stored error history, a component test sequence (valves, pump, motor, heater), and sensor readings (level frequency, thermistor). It's the difference between guessing at a 3C and watching the motor test fail in front of you.
Entry patterns (and why yours needs the sheet)
Samsung platforms have used combinations involving Delay End, Temp/Spin option keys held through power-on, varying by generation (EcoBubble-era, AddWash-era, current AI models all differ). The tech sheet — usually in a plastic pouch inside the rear panel or under the top cover — prints your model's exact entry and step table. Forums will confidently give you another generation's combination; the sheet is the only safe source.
Smart Check / SmartThings
App-connected Samsung washers offer Smart Check: the machine self-diagnoses and reports faults to the SmartThings app, including some that never reach the display. If your model has it, run it before opening panels — it's the intended first diagnostic, and its report names the system to open.
Calibration mode: the one diagnostic Samsung documents step by step for owners
Against this page's correct warning that Samsung publishes no universal service-mode sequence, one owner diagnostic is documented completely, and it deserves its full text. Calibration mode recalibrates the washer's weight detection — the sensing the machine uses to adjust the water amount per cycle — and Samsung recommends it before the first wash after installation, after any move, and whenever the weight-detection value may have changed. Samsung's support procedure for front-loaders runs: remove all laundry and any other contents from the machine; power the washer off and back on; hold Temp. and Delay End (+) simultaneously for three seconds to enter Calibration mode, at which point the Cb message appears on the display; press START/PAUSE to run the cycle; the drum rotates clockwise and counterclockwise for about three minutes; when the cycle completes, 0 appears on the display and the washer turns off automatically. Samsung's general guidance puts the duration at three to five minutes depending on the model, and its washer information page describes the same mode (spelled Cb or C6 on the display) as rotating the tub back and forth for one to three minutes and ending by itself. Two conditions are absolute in every version: the tub must be empty — Samsung's information page warns the mode 'will not calibrate correctly unless the washing machine is empty', and directs you to remove anything in it and run Calibration again — and the panel design differs between models, so a button labelled differently on yours sends you to the manual's version of the same three-second hold. Note what calibration is not: it reads no fault codes and clears none. Owners reach for it during the error-code-retrieval phrases this page is searched by, and its honest place in that workflow is narrow and real — after a move, a levelling change or suspension work, it re-teaches the machine its own empty weight, and an unbalance complaint investigated without it has skipped a documented step.
Smart Check, exactly as the manual prints it
The base sections introduce Smart Check as a feature; Samsung's manuals give it as a procedure, and the procedure's details decide whether it works. From the washer manual text: the prerequisite is the Samsung Smart Washer app, downloaded from the Play Store or App Store and installed on a mobile device with a camera — the function is optimised for Galaxy and iPhone devices, on applicable models only. When the washing machine detects an issue, an information code appears on the display; to enter Smart Check mode, press and hold Rinse and Spin simultaneously for three seconds. The washer then starts its self-diagnosis procedure and displays an information code if a problem is detected. Run the app, tap Smart Check, and hold the mobile device close to the washer's display so the smartphone camera and the display face each other — the app recognises the information code automatically and provides detailed information about the problem with applicable solutions. The manual's two failure notes are the troubleshooting: if the washer reflects light on the display, the app may fail to recognise the code (shade the display and retry), and if the app fails to recognise the Smart Check code consecutively, enter the information code manually on the app screen. The function name itself may differ by language. Compare this with the generic advice to 'scan the code with your phone': Samsung's version has a definite entry hold (Rinse + Spin, three seconds), a definite failure mode (reflected light), and a definite fallback (manual entry) — and it begins from a displayed code, which is why Smart Check complements rather than replaces reading the display first.
Displays that imitate faults during diagnosis: Cb, CL and dn
Three displays owners meet while hunting for diagnostics are documented Samsung statuses, and each has wasted service calls when read as a fault. Cb (or C6) is Calibration mode, covered above: the tub rotates back and forth for a few minutes and the mode ends by itself; if you entered it accidentally, the correct response is to let it finish on an empty tub, not to cut the power mid-measurement. CL, on newer washers, is Child Lock — but Samsung's washer page gives it a specific behaviour worth knowing before you judge it: the code displays when Child Lock mode has drained water from the tub, which it does whenever Child Lock is on, the water level is unsafe, and the door has been opened; to clear it, turn the washer off and back on, or turn Child Lock off. The related door-error section adds the timing — if the door is not closed or Child Lock not turned off within 30 seconds in that state, the machine drains the tub — so a washer that empties itself and shows CL after a child opens the door mid-cycle is executing a documented safety sequence, not leaking or faulting. dn is downloading: the washer is downloading an update, the controls (including the dial) will not respond while it runs, updates take about 15 minutes, and the message disappears when the download completes — keep the washer powered on throughout. Only a dn displayed for more than 30 minutes of continuous power with no Wi-Fi connection issues earns Samsung's service route. All three displays share the diagnostic moral: a mode announcement is the machine telling you what it is doing, and the retrieval work begins only when the display is a fault code.
Error-code retrieval, honestly: what Samsung puts in owners' hands
The retrieval phrases in this page's search traffic ('error code mode', 'error code retrieval') deserve a direct inventory, because Samsung's owner-level diagnostic toolkit is real but specific, and it does not include a stored-history browser. What Samsung documents for owners is: the fault code on the display itself, reported by the machine's own monitoring at the moment of failure; Smart Check, which reads that displayed code and returns Samsung's analysis of it (previous section); Calibration mode, which is a measurement procedure, not a code reader; and, on app-connected models, the SmartThings device reporting the base sections describe. Stored fault history — the codes from last month that no longer show — exists on these machines, but Samsung keeps its retrieval in the model-specific service documentation the base sections point to: the tech sheet inside the machine, which prints your model's entry sequence and test table. The workarounds circulating in owner forums (button sequences borrowed from other generations, community-discovered history browsers) are not Samsung's owner procedure for any model, and this page does not promote them to one — the Batch rule for this guide stands: sequences come from your sheet or not at all. The practical consequence is a habit, not a procedure: because the display is the owner's only guaranteed record, photograph every fault code when it appears, with the cycle and stage noted. That photograph is your stored history, and on a machine whose code later clears itself, it is the entire difference between a service visit that starts from evidence and one that starts from a shrug.
Leaving a diagnostic session cleanly
Each documented mode has its own documented exit, and using it matters because a washer left in a mode imitates a fault at the next power-on. Calibration ends itself: 0 on the display, then the machine turns off automatically — no exit action exists or is needed. Smart Check ends when you put the phone down: the machine has displayed its code and the app has read it, and normal operation resumes from the panel; the code that prompted the session remains a live report, so a cycle run afterwards is a test of the fault, not a formality. The statuses clear on their own terms too: CL by powering off and on or turning Child Lock off, dn when the download completes. If a session of any kind leaves the display frozen on something none of Samsung's lists recognise, Samsung's washer page gives the generic sequence for its all-other-errors group — power off for two to three minutes, power back on, restart the cycle, and request service if the error continues — which is the correct ceiling for owner recovery here. After any session, run one short ordinary cycle and watch it complete: a machine that fills, washes, drains and spins normally is back in user state, and one that stops has just given you the fresh, photographable code that the whole diagnostic exercise exists to produce.
Top-load calibration differs in detail — use your loader's version
Samsung publishes its calibration procedure per loader family, and the top-load version is not the front-load version with the lid moved. In Samsung's regional procedure for top-loaders, you remove all contents, hold Temp. and Delay End simultaneously for at least three seconds with the power already on, then press and hold START/PAUSE to activate calibration mode; the front-load procedure instead powers the machine off and on first, uses the same three-second Temp. and Delay End (+) hold to bring up the Cb message, and starts the cycle with a press of START/PAUSE. The family's shared constants matter more than the choreography differences: the tub must be empty in both, the drum or tub rotates in both directions while the machine measures, a 0 on the display marks completion, and the washer turns itself off automatically at the end. Samsung's support pages are themselves slightly inconsistent about duration — about three minutes in the front-load text, three to five minutes in the general guidance — because duration is model-dependent, which is the same reason the button choreography is: this guide prints the documented variants so you can recognise your model's, and your manual remains the authority for which one you own. The practical warning follows from the variance: a calibration entered with the wrong family's steps usually does nothing at all (no Cb, no rotation), and that nothing is information — it tells you the sequence was not your model's, not that the machine is dead.
Key takeaways
- Photograph the tech sheet the first time you find it; it will try to disappear into the machine's insulation forever.
- Record stored codes before clearing the history — same rule as every brand.
Resetting the Samsung washer
On Samsung washers most fault codes clear with a power reset: switch the machine off, unplug it (or trip the breaker) for at least 5 minutes so the control board fully discharges, then restore power and run a short Rinse+Spin or a small test load. If the code was caused by a one-off condition — a kinked hose, an unbalanced load, a suds spike — it will not come back. If it returns on the next cycle, the control has detected the same fault again and the reset has only cleared the message, not the cause. Samsung does not use a button-combination 'master reset' on most models; the power cycle is the reset.
Related guides
Facts on this page were checked against manufacturer documentation: www.samsung.com · www.samsung.com · www.samsung.com · www.samsung.com