R-Pro › Field cases › Air conditioning
Samsung AC E/C Error Code Master — E101/E102/E121/E122/E151/E152
Likely causes
Step 1 — Code meanings + try self-reset first
Check: **E101/C101** = check outdoor power/breaker or reset indoor. **E102/C102** = outdoor→indoor comm error. Inspect wiring and termination. **E121/C121** = indoor ROOM temp sensor SHORT/OPEN. **E122/C122** = indoor Eva_in sensor SHORT/OPEN (evaporator inlet). **E151/C151** = indoor EEV open-fault stage 2. **E152/C152** = indoor EEV close-fault stage 2. **First-visit try**: power OFF 10s → ON → wait 3–4 min for comm → ~50% resolved (simple memory error).
What to do: **E101/E102**: check wiring first (swapped L/N most common). Replace 14/4 cable if open. Verify termination resistor DIP. If still bad, suspect PCB comm IC. **E121/E122**: replace NTC with same spec (10 kΩ @25°C). Check cable continuity too. **E151/E152**: measure EEV coil resistance (normal 40–60 Ω). Replace coil only if open. Coil OK but no operation = disassemble/clean or replace EEV body.
**Field trick**: Samsung/LG have systematic codes (LG=CH, Samsung=E/C; C is exterior display, E is interior, same meaning). On first visit, always power OFF 10 sec and wait 3–4 min comm before diagnosis. ~50%+ are simple memory errors. **E151/E152 EEV** spikes 3–4 weeks after season starts (coil signal precision). Repeating = consider EEV body replacement.
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