AC Error Codes · Samsung
Samsung AC Error Codes: What They Mean & What to Do
Find your code, understand what it means, then run a guided diagnosis.
Error Code Finder
Look a code up against sourced manufacturer records. Codes we cannot source are not listed — a guessed meaning is worse than no meaning.
Samsung uses two numbering conventions, and knowing which one you are reading matters more than the code itself. Service documentation and DVM (VRF) systems use three-digit codes with an E prefix — E101, E121, E554 — where the first digit block identifies the fault area. Samsung's own support material for indoor units uses much shorter two-character codes for some of the same faults. Our research found this discrepancy explicitly, reflecting different product generations or regional firmware.
How do Samsung AC error codes work?
On the three-digit system, E1xx codes are indoor-side faults (E101 and E102 are indoor-to-outdoor communication, E121–E130 are indoor sensor faults), while E2xx and E5xx codes come from the outdoor unit or DVM system — E554 is gas-leak detection. On some indoor units Samsung instead shows a short two-character code such as C1 or 21 for a room-sensor fault. Codes appear on the indoor display, the wired controller, or a service tool.
Product families covered
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Residential split (E1xx generation)
Three-digit E-prefixed codes on the indoor display, controller or service tool.
-
Indoor display (short-code generation)
Two-character codes documented on Samsung's own support pages.
-
DVM (VRF)
Shares the three-digit architecture and adds outdoor and system-level E2xx / E5xx codes across many indoor units.
Where the code is displayed — and why it matters
The same fault can be labelled differently depending on which display you read it from, so identify the display before looking the code up.
- Indoor unit display
- Shows either the three-digit code or the short two-character code, depending on generation.
- Wired wall controller
- Usually shows the full three-digit code, and on DVM installations the affected indoor unit address.
- DVM outdoor unit / service tool
- System-level and outdoor faults are read here rather than at a single room display.
Samsung three-digit code blocks
The number block identifies where the fault was detected:
- E1xx
- Indoor-side faults — communication, sensors, expansion valve
- E2xx
- Outdoor and inter-unit communication faults
- E5xx
- System-level faults including refrigerant / gas-leak detection
- 2-character
- Short indoor-display codes on other generations — same faults, different labels
How the families differ
- E101 (indoor receives no data) and E124 (the same loss reported at the outdoor unit) describe one broken link seen from two ends — record which unit is displaying the code.
- On DVM systems the same communication fault can appear on many indoor units at once, because they share one bus with the outdoor unit.
- A short two-character code and a three-digit E1xx code can describe the same fault on different generations. They are parallel labels, not different problems.
Samsung split / DVM three-digit codes
Compiled from Samsung service documentation and cross-checked technical references. On DVM systems the code is usually accompanied by the address of the affected indoor unit.
| Code | What it reports | Applies to | Severity | Source |
|---|---|---|---|---|
| E101 Diagnose | Indicates communication error — the indoor unit receives no data from the outdoor unit | Residential split (E1xx generation) · DVM | High | B |
| E102 | Indicates communication error between the indoor and outdoor unit (shown on the indoor unit) | Residential split (E1xx generation) · DVM | High | B |
| E121 | Indicates room temperature sensor fault (open or short circuit) | Residential split (E1xx generation) · DVM | Moderate | B |
| E122 | Indicates evaporator-in temperature sensor fault (open or short circuit) | Residential split (E1xx generation) · DVM | Moderate | B |
| E123 | Indicates evaporator-out temperature sensor fault (open or short circuit) | Residential split (E1xx generation) · DVM | Moderate | B |
| E124 | Indicates communication error between indoor and outdoor unit (shown on the outdoor unit) | Residential split (E1xx generation) · DVM | High | B |
| E125 | Indicates mid 2 temperature sensor fault (indoor) | Residential split (E1xx generation) · DVM | Moderate | B |
| E128 | Indicates evaporator-in sensor detached from the pipe | Residential split (E1xx generation) · DVM | Moderate | B |
| E130 | Indicates evaporator-in and evaporator-out sensors both detached simultaneously | Residential split (E1xx generation) · DVM | Moderate | B |
| E151 | Indicates eEV opening error (indoor, second detection) | Residential split (E1xx generation) · DVM | High | B |
| E554 | Indicates gas leak detection | Residential split (E1xx generation) · DVM | High | B |
Samsung short indoor-display codes
Documented on Samsung's official support material for indoor units. Where a short code and a three-digit code describe the same fault, we flag the numbering discrepancy rather than merging the two systems.
| Code | What it reports | Applies to | Severity | Source |
|---|---|---|---|---|
| CI | Indicates auto-clean function status — not a fault | Indoor display (short-code generation) | Low | A |
| C1 / 21 | May indicate, depending on model defective room temperature sensor Samsung documents this fault as a short code (C1 / 21) on the official support page, while service compilations use the three-digit E1xx system (E121) for a room-sensor fault. The two numbering systems appear to belong to different product generations or regional firmware, so the code must be read against your unit's own generation — we publish the discrepancy rather than merging the tables. | Indoor display (short-code generation) | — | M |
Full guides for high-demand Samsung codes
Codes without their own guide are answered in the table above. We only give a code its own page when there is genuinely more to say than a table row can hold.
Before you act on a code
- Do not assume a two-character code and a three-digit code share a numbering logic — the generations differ, and reading one table against the other produces a wrong diagnosis.
- E554 (gas-leak detection) and E151 (expansion-valve error) are refrigerant-circuit faults: switch the unit off and have it inspected rather than continuing to run it.
- The three-digit table is compiled from strong secondary service material rather than a single official Samsung PDF — verify against your model's service manual before parts are replaced.
Corroborated across independent technical sources
How to identify your system
- Note whether the code has three digits (E101) or two characters (C1 / 21) — that identifies which Samsung table applies.
- Note which unit is displaying it: indoor display, wired controller, or outdoor / DVM side.
- Photograph the indoor unit's model label, and on DVM systems record the indoor unit address shown with the code.
No code showing? Start from the symptom
Samsung error codes — common questions
What does Samsung E101 mean?
E101 means the indoor unit is receiving no data from the outdoor unit — an indoor-to-outdoor communication failure. Common causes are a loss of power to the outdoor unit, damaged or disturbed interconnecting wiring, and control-board failure.
Why do E101 and E124 look like the same fault?
They are the same broken communication link reported from different ends: E101 is logged by the indoor unit, E124 is reported at the outdoor unit. Recording which unit displayed the code helps a technician start at the right end.
My Samsung shows a two-character code, not E-something. Why?
Samsung has used more than one numbering convention across generations and regions. Some indoor units display short two-character codes for faults that service documentation lists as three-digit E1xx codes. Confirm your model before matching a code to a table.
Is E554 serious?
Yes — it indicates gas-leak detection in the refrigerant circuit. Turn the system off and have it inspected. Running a system with a refrigerant loss risks compressor damage, and the leak itself needs finding and repairing rather than simply topping up.
Need this looked at properly?
Call or send a photo on WhatsApp and we will tell you whether it needs an inspection, and what the work involves, before anyone travels.
Sources consulted
- Samsung official support page — indoor air conditioner error codes
- Samsung split / DVM error-code service compilations (strong secondary, mutually consistent)