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Error code · Microwave

Code 1d21 on a Whirlpool Built-In Microwave: Sensor and Control Reading

Whirlpool built-in microwaves and microwave drawers show 1d21 when the oven temperature sensor, the control, or their shared wiring is reporting a problem. Model WMC50522AS is one example of the platform. The code is a circuit…

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Code
1d21
Appliance
Microwave
Brand
Whirlpool
Warranty
30-day workmanship

What 1d21 means

Whirlpool built-in microwaves and microwave drawers show 1d21 when the oven temperature sensor, the control, or their shared wiring is reporting a problem. Model WMC50522AS is one example of the platform. The code is a circuit report: it tells us the sensing path needs checking, and it does not prove a particular part is dead. The oven may stop heating or refuse a function while the message is up.

Common causes of 1d21

  • Temperature sensor signal the control cannot accept
  • Control reading the sensor incorrectly
  • Damaged or loose sensor wiring
  • One-time glitch that goes away after a restart
✓ One safe check you can try

1. Shut the microwave breaker off and wait one minute. 2. Turn the breaker on. 3. Stay with the oven for one minute and check that 1d21 does not come back. 4. Test with a brief cooking run. 5. Do not open the cabinet if the code returns; call us.

! Why to stop there
  • If 1d21 appears again, we check the sensor, the control and the connectors in order
  • Testing first means you pay only for the part that needs replacing
  • Price in writing before work and 30 days of workmanship warranty
Opening a panel yourself does not automatically cancel a manufacturer warranty, but it can cause accidental damage, and some manufacturers set their own service conditions. Check your warranty terms, or ask us, before deciding.
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Other Microwave codes

F9Q1F9Q1 on a Whirlpool Over-the-Range Microwave: Touch Pad Circuit FC E1Whirlpool Over-the-range Microwave Wi-Fi Code FC E1: Weak Signal FC E2FC E2 on a Whirlpool OTR Microwave: Router Connection Lost FC E3Whirlpool Over-the-range Microwave Showing FC E3 for Wi-Fi: Module Check FC E7Whirlpool OTR Microwave Connection Code FC E7: Appliance Not Reaching the Internet FC E8Whirlpool OTR Microwave Registration Code FC E8: Entry Mistake FCE8Whirlpool Over-the-range Microwave Registration, FCE8: Wrong Model Selected Feature Not Available or Fault DetectedWhirlpool Built-in Microwave Message "Feature Not Available": Retry or Cut Power
1d211d21 questions
What causes 1d21 on a built-in microwave?

The oven temperature sensor, the control or the wiring between them is reporting a problem. A power reset clears a one-time glitch; a recurring code means one of those three needs a test.

Is it safe to try the breaker reset for 1d21?

Yes. Switch the breaker off for one minute, back on, and watch the oven. Do not open the cabinet. Sensor and control work is for us, with the unit disconnected.

Do you fix microwave drawers with this code?

Yes, built-in microwaves and drawers both. Older ones are still in many homes here, and we say plainly if a repair is not worth it.

Book a visit

Still seeing 1d21?

A technician diagnoses it on site and gives you the price in writing before any work starts.

(713) 589-6107