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Error code · Microwave

Whirlpool Built-In Microwaves and Drawers Code 4d12: Latch and Switch Circuit

A 4d12 code on Whirlpool built-in microwaves and microwave drawers, model WMC50522AS among them, concerns the door latch assembly, the door switch, or the wiring connected to them. The oven checks that the door is closed…

Medium · inspection needed
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Code
4d12
Appliance
Microwave
Brand
Whirlpool
Warranty
30-day workmanship

What 4d12 means

A 4d12 code on Whirlpool built-in microwaves and microwave drawers, model WMC50522AS among them, concerns the door latch assembly, the door switch, or the wiring connected to them. The oven checks that the door is closed and latched before it runs, so a problem in that circuit shows up as a code and an oven that will not start or stops mid-cycle.

Common causes of 4d12

  • Door latch assembly not registering a closed door
  • Door switch contact problem
  • Wiring or connector to the latch or switch
  • Brief glitch cleared by a restart
✓ One safe check you can try

1. Close the door firmly and make sure nothing sits in the door seal area. 2. Turn off the microwave breaker for one minute. 3. Turn it back on. 4. Watch the oven for one minute to confirm 4d12 stays away. 5. Check that a quick cooking cycle works again.

! Why to stop there
  • If 4d12 remains, we test the latch assembly, the switch and the wiring in turn
  • A door that looks closed can still miss the switch, so we check alignment too
  • The price is in writing first, and repairs have a 30-day 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

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 LOCWhirlpool Microwave LOC on the Display: Control Lock Is On
4d124d12 questions
Why does 4d12 appear when my door is shut?

The oven may not be getting a closed-and-latched signal. The latch, the door switch or the wiring could be responsible, so we test them in order instead of replacing parts on a guess.

Is a microwave with a latch code safe to use?

The oven is designed not to run if it cannot confirm the door. Do not defeat or bypass the latch. Leave it off and call us if the code remains.

Can older built-ins get a new latch?

In many cases yes. Older units are common in Houston, and we weigh repair cost against the value of the oven and tell you honestly.

Book a visit

Still seeing 4d12?

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

(713) 589-6107