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Error code reference

Amana Oven Error Code 21

RTD (temperature sensor) shorted; may display repeatedly if room temperature is too low.

Amana codesAmana oven codes

RTD (temperature sensor) shorted; may display repeatedly if room temperature is too low.

First step from the service manual

Verify room temperature is not too low.

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

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  • Wiring diagram references and connector pinouts from the OEM service manual
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What 21 means on a Amana oven

Error code 21 on an Amana oven indicates that the RTD (Resistance Temperature Detector) sensor circuit is reading a shorted condition. The RTD is a probe-style temperature sensor mounted inside the oven cavity that continuously monitors internal temperature and sends resistance-based signals to the electronic control board. Under normal operating conditions, the RTD sensor resistance increases proportionally with temperature, allowing the control board to regulate heating elements accurately. A shorted RTD circuit means the sensor or its wiring is producing an abnormally low resistance reading, which the control board interprets as an implausibly high temperature signal.

Before assuming a faulty component, it is important to note that this error can appear repeatedly when the ambient room temperature is too low. Cold conditions can affect sensor resistance readings and cause the control to misinterpret the signal as a short. This is why the first diagnostic step is to confirm that the room temperature is within a normal operating range before proceeding with component-level testing.

If the room temperature is adequate and the error persists, the fault typically lies in the RTD sensor itself, its wiring harness, or the connection at the control board. A true short in the RTD circuit can result from a damaged sensor element, pinched or melted wiring, or a corroded connector causing two conductors to make unintended contact. Testing the RTD sensor resistance with a multimeter and inspecting the wiring from the sensor to the control board are the key steps in isolating the fault.

Source: manufacturer service documentation.

Common causes of 21

  1. 01

    Low ambient room temperature

    Wiring / connection

    Cold room conditions can cause the RTD sensor to produce resistance readings that the control board misinterprets as a shorted circuit. Check that the room temperature is at a normal indoor level before proceeding with any component testing.

  2. 02

    Faulty RTD temperature sensor

    Part replacement

    The RTD probe itself may have developed an internal short, producing a resistance value that falls outside the acceptable range. Testing the sensor with a multimeter and comparing the reading to the expected resistance at room temperature can confirm this failure.

  3. 03

    Damaged or pinched sensor wiring

    Part replacement

    The wiring harness running from the RTD sensor to the control board can become pinched, melted near a heating element, or otherwise damaged, causing two conductors to contact each other and create a short. Visually inspect the entire wiring run for signs of wear or heat damage.

  4. 04

    Corroded or loose sensor connector

    Wiring / connection

    Corrosion or a loose connection at the RTD sensor plug or at the control board connector can cause intermittent or persistent shorted-circuit readings. Disconnect and inspect both ends of the connector for moisture, corrosion, or bent pins.

  5. 05

    Failed electronic control board

    Part replacement

    If the RTD sensor and all wiring test within normal specifications, the control board itself may be misreading the sensor input due to an internal component failure. This is the least common cause and should only be considered after ruling out the sensor and wiring.

See the test procedure for each cause

Frequently asked questions about 21

What does 21 mean on a Amana oven?
Error code 21 on an Amana oven indicates that the RTD temperature sensor circuit is detecting a shorted condition. The control board monitors the sensor's resistance to regulate oven temperature, and a short causes an abnormal low-resistance reading. This code can also appear repeatedly if the room temperature is unusually cold, triggering a false short reading. Confirm room temperature first, then inspect the sensor and its wiring if the error continues.
Can I fix error code 21 on my Amana oven myself?
In some cases, yes. If the error is triggered by a cold room, simply allowing the room to warm up may clear the fault. If the issue is a loose or corroded connector, cleaning and reseating it is a manageable DIY repair. Replacing the RTD sensor is also a relatively straightforward repair for someone comfortable working with appliances, though it does require disconnecting power and accessing the oven cavity. Control board replacement is more complex and may warrant professional service.
Is it safe to use my Amana oven when error code 21 is displayed?
It is not recommended to operate the oven while error code 21 is active. A shorted RTD sensor means the control board cannot accurately monitor the oven's internal temperature, which could lead to overheating or unreliable cooking performance. Discontinue use until the sensor circuit has been inspected and confirmed functional.
Will resetting my Amana oven clear error code 21?
A reset, typically done by disconnecting power for a few minutes and restoring it, may temporarily clear the error. However, if the underlying cause is a shorted sensor, damaged wiring, or a faulty connection, the code will return once the oven attempts to operate. A reset is useful for confirming whether the fault is persistent or intermittent, but it does not repair the root problem.
How much does it cost to repair error code 21 on an Amana oven?
Repair costs depend on the root cause. If only the RTD temperature sensor needs replacement, parts typically range from around $20 to $60, with professional labor adding $75 to $150 or more depending on the service provider. If the control board is at fault, parts alone can range from $100 to $250 or higher, plus labor. Diagnosing the exact cause before ordering parts is strongly recommended to avoid unnecessary expenses.

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