What E21 means
E21 means the control board found the thermal sensor circuit open, as if the sensor were unplugged or a wire broken. Without that reading the control cannot regulate heat, so do not cook with the oven until the code clears and stays clear after a reset.
Error codes
Reference| Code | Meaning |
|---|---|
| E21 | The Thermal Sensor circuit reported open to the control board. There may a problem with the Thermal Sensor, the Appliance Control Board, or the associated wiring. |
What the oven does alongside E21
- E21 on the display and no heat — Bake or broil is cancelled or never starts.
- Chimes or a flashing display — The control keeps signalling until the code is acknowledged or the power is cycled.
- The code returns the moment power is restored — A hard open, such as a broken lead or failed sensor, comes straight back; a code that stays away for days suggests a loose connection.
- NEAR MISS: the oven runs hot or cold with no code — That is a drifting sensor, a different problem; E21 is the all-or-nothing version.
What triggers E21, most likely first
- A failed thermal sensor — Ranked first: the sensing element breaks open with age and repeated high-heat cycles.
- A connector that has backed off or corroded — Its plug sits in a hot zone, and heat cycling loosens or oxidises the terminals.
- A broken wire between sensor and board — A lead stretched when the range was moved, or chafed at a panel edge, can part inside its insulation.
- The Appliance Control Board's sensor input — Last and costliest, condemned only after the sensor and wiring test good.
Check order for E21, and why
- Power-cycle at the breaker — Free, and it separates a hard open from an intermittent one before anything is touched.
- Look at the sensor and its lead, oven cold — A sensor out of its mount or a lead pulled tight is visible without tools.
- Measure the sensor at its connector — An open reading condemns the sensor; a normal one moves the search to the wiring.
- Check continuity to the board — Only after the sensor tests good: the board is the least likely part and the dearest.
Reset and owner-safe checks
- Clear the code with a power-down — Breaker off for a minute, then on; note whether E21 returns at once, during preheat, or not at all.
Tools: breaker panel accessAbout 3 min
- Inspect the sensor and lead — Oven cold and power off: check the sensor sits firmly in its mount and its lead is not pinched.
Tools: flashlightAbout 5 min
- Reseat the connector — On many ranges the plug pulls through the cavity wall once the sensor's screws are out; look for dark terminals and push it back firmly.
Tools: screwdriver, flashlightAbout 15 min
- STOP before anything live — Powered measurements and anything behind the back panel belong to a technician.
Before any panel comes off
Safety
Switch off the breaker or unplug the range before removing the sensor's screws or any panel; a capacitor can hold a charge after the power is off. Let the oven cool fully first. On a gas range, if you smell gas, do not switch anything on or off, leave the building, and call the gas utility or emergency services from outside.
When E21 needs a technician
Call when E21 returns after a power-down, when the connector shows heat damage, or when a new sensor does not clear it. An open that survives a good sensor lies in the harness or on the Appliance Control Board, and tracing it means pulling the range out.
Other Amana oven codes
Which models this reading covers
This reading of E21 applies to Amana ovens whose control reports the thermal sensor circuit as the table describes; other Amana controls use other code formats for sensor faults. Where a model-specific page exists, it is the better answer. None is listed for E21 yet, so start at the Amana oven code index below.
Amana oven code index
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