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Samsung Oven C-21 Error Code: Temperature Sensor Failure Fix

Quick Answer

Samsung ovens use an NTC thermistor rated at 10K ohms at 77 degrees F - this is the most important spec to know for C-21, because it is radically different from the RTD probes used by GE (1080 ohms) and Frigidaire (1100 ohms). Ordering a GE or Frigidaire sensor as a substitute is the most common and costly Samsung C-21 mistake.

I've been doing this fifteen years and C-21 is almost never a total sensor blackout. It's usually a drift issue where the oven thinks it's at 400 degrees when it's stone cold. Moisture from steam cooking or a self-clean cycle messes with the sensor's internal resistance over time. If your oven shuts down the second you hit start, you're probably looking at a harness problem or a completely dead probe.

SamsungOvenSeverity: high84% DIY Success
Time to Fix
20–45 min
Difficulty
beginner
Parts Cost
$15 – $250
Tools Needed
Multimeter (ohm mode), Phillips screwdriver

What Does the C-21 Code Mean?

When this code pops up, your Samsung's flying blind. It can't safely verify the temperature, so it kills the heating circuit immediately. Looks like a major control board failure, but it's almost always a simple communication breakdown between the sensor and the board. I always check the plug behind the back panel first for signs of heat damage before I do anything else.

Most Likely Causes

Based on aggregated repair data, here is the probability breakdown for this error code:

NTC thermistor probe internal failure (drift or open circuit)40%
Sensor wiring harness damaged or connector loose24%
Control board sensor input circuit failure (rare)22%
Moisture in sensor connector causing resistance shift14%

Symptoms You May Notice

  • C-21 shows on the control panel and won't clear no matter how many times you hit cancel.
  • You set a bake temp and the oven quits before it even starts heating, sometimes within just a few seconds of pressing start.
  • Code pops up when the oven is completely cold, which tells you right away it's a resistance reading problem and not something thermal.
  • Before it fully died, the oven was running 50 to 100 degrees colder than the display showed and food kept coming out undercooked.
  • The error comes and goes for a while, works fine for a few days then C-21 shows up again. That on-and-off pattern usually points to a loose connector rather than a dead probe.

Can you reset a Samsung oven to clear the C-21 code?

Flip the breaker off for a full minute, then back on. That'll clear the display. But don't expect it to stick if the sensor's actually drifted out of its 10K ohm range. The control board's going to flag C-21 again the second you try to preheat. This isn't a software hiccup you can reset away, it's a hardware safety lockout. Fix the underlying problem first, then reset.

Tools Required for Diagnosis

Multimeter (ohm mode)Phillips screwdriverNut driver (1/4")Flashlight

Diagnostic Checklist

Follow these steps in order. We start with the easiest external fixes before opening up the machine.

ComponentComponent Under Test
Expected Range9500–10500 ohms
ConditionIf Open (OL) or infinite, replace component.

Replacement Parts

If your diagnostic testing proves the component has failed, you will need a replacement. We recommend OEM parts over aftermarket for water-handling components.

Part Name
Samsung NTC Temperature SensorDG32-00002B · $15–$35
Samsung Oven Control BoardDG92-01099A · $120–$250

Frequently Asked Questions

How do I test a Samsung NTC oven sensor at home?
The oven's got to be at room temp for this to mean anything. Set your multimeter to ohms. Unplug the sensor from the wiring harness and touch your leads to the two pins on the sensor connector. At 77 degrees, you're looking for 10,000 ohms. If your kitchen's colder it'll read a little higher, warmer a little lower, that's just how NTC sensors work. But a reading like 1,100 ohms or OL means it's definitely bad. Don't let anyone talk you into a cross-brand substitute, the resistance spec is everything with these.
Can I use a GE or Frigidaire temperature sensor in a Samsung oven?
No. And I can't stress that enough. They look almost identical, same connector, same mounting holes, practically the same part visually. But GE and Frigidaire use RTD sensors that sit around 1,100 ohms at room temp. Put one in a Samsung and the board sees that low resistance and thinks the oven's already scorching hot. It'll trigger C-21 instantly or kick a runaway temperature error. Always use the Samsung-specific 10K NTC part. DG32-00002B is the one you want, don't improvise on this one.
Does Samsung C-21 mean the oven is unsafe to use?
Stop using it when you see C-21. The control board can't tell if the oven's at 70 degrees or 700 degrees, so it can't safely cycle the heating elements. Usually the software shuts everything down as a precaution, but you don't want to be testing whether that safety circuit works every single time you bake. I've seen boards where the safety shutoff itself had problems. It's a major safety fault, not a nuisance code. Fix it before you use the oven again.
How much does it cost to fix a Samsung oven C-21 error?
The sensor itself is usually $15 to $25 online, part number DG32-00002B. If you're doing it yourself, that's basically your whole cost. If you're calling a tech, figure $150 to $250 total with labor. The control board is the expensive scenario, those run $200 to $400 just for the part. But honestly, in probably 90% of the C-21 calls I've been on, it was the sensor or the wiring. I've replaced a board specifically for C-21 maybe twice in fifteen years. Start cheap.
How long does it take to replace the Samsung oven temperature sensor?
If you've done it before, it's a 20 minute job. First time? Give yourself 45. You'll spend most of that pulling the range out and getting to the back panel, not actually doing the repair. The sensor swap itself is just two screws and a clip connector. Take your time with the back panel because those sheet metal edges will cut you if you're rushing. This is genuinely one of the more beginner-friendly oven repairs out there, as long as you've got a multimeter to verify the fix actually worked.

Related Samsung Oven Error Codes

Code: HUBSamsung Oven Error Codes: C-21, C-F2, C-24, C-A2 Complete GuideCode: C-F2Samsung Oven C-F2 Error Code: Temperature RunawayCode: C-24Samsung Oven C-24 Error Code: Lower Oven Sensor Fault

Same Fix Works on These Brands

Samsung shares the same hardware platform with these brands. The diagnosis and repair steps are identical.

Samsung washerSamsung Washer 3C2 Error Code: Motor StallSamsung washerSamsung Washer 3E Error Code: Motor FaultSamsung washerSamsung Washer 4E Error Code: Water Supply Fault (Top Load)Samsung washerSamsung Washer 5C Error Code: Drain Error (Older Display)Samsung washerSamsung Washer 8C Error Code: Vibration Sensor FaultSamsung washerSamsung Washer 8E Error Code: Motor Frequency Sensor Fault

Models Known to Experience C-21 Errors

This repair applies to most Samsung ovens with this error code. Common model numbers include:

NE59M6850SS, NE63T8911SS, NE59J7630SS, NE63A6511SS, NE58F9710WS, NE59T4321SS, NE63A6511SW, NE63BB8714AB

MS

Written by

Mike Sullivan

Lead Appliance Repair Technician · 20 years experience

Last verified for technical accuracy on March 14, 2026