Speed Queen Commercial Washer Error Code EC:27: Write Test Failed
EC:27 means the card reader's built-in card write test failed. The manual calls it a bad card reader that may need to be replaced. Customers cannot fix it by changing cards, so note the code and arrange service.
Medium: card payment is unreliable until the reader is replaced, but the manual does not describe any hazard.
- Code
- EC:27
- Maker
- Speed Queen
- Equipment
- Washers
- Applies to
- Speed Queen/Alliance commercial automatic washers H002C: EDC (Micro-wand IIIe) models, MDC models, NetMaster models (model numbers p. 6)
What does Speed Queen error code EC:27 mean?
Besides handling cards, the reader on a Speed Queen commercial washer can test itself. One of its built-in tests exercises the card writing function with no customer card involved. EC:27, shown as “Diagnostic Test Card Write Failure”, is the result when that self-test does not pass.
The key difference from EC:26 is where the problem is. EC:26 follows an attempt to write to a customer's card and points first at the card. EC:27 comes from the reader's own test, so the card is not the suspect. The manual describes it as a bad card reader and says the reader may need to be replaced. No causes are listed, and the manual gives no reset step or retry. In practice the washer's payment function is unreliable until the reader is dealt with, even if the code appears only now and then.
Affected models and control systems
Speed Queen/Alliance commercial automatic washers covered by troubleshooting guide H002C: the EDC (Micro-wand IIIe) models, the MDC models and the NetMaster models. The guide lists the model numbers on its page 6.
Code numbers and their meaning can change between control generations. We match the full model and control before acting on a code.
What you may notice
- EC:27 shown on the display, often after power-up
- Card payments do not work or behave unpredictably
- Changing to a different card makes no difference
Possible causes
Likely causes — what usually sits behind error code EC:27 on this control. A technician confirms which one it is before any part is replaced.
- Writing circuit in the reader degraded with age
- Supply voltage to the reader sagging because of a poor connector
- Static or a power event damaging the reader electronics
Safe checks before calling for service
- Record the code and when it appears, for example at power-up or after a card is inserted.
- Try a second card. If the same code shows, the cards are not the cause.
- Switch the machine off at its normal operating switch, wait about a minute, and switch it on to see whether the code returns.
- For the service call, tell the technician whether EC:27 returns every time or only sometimes.
How a technician diagnoses error code EC:27
- Confirm the code repeats after a full power-down and restart.
- Inspect the reader and its cable for visible damage or loose connections with the power off.
- Check the supply to the reader with a meter where the wiring allows it.
- Swap in a known good reader to see whether the self-test passes.
- Replace the reader once the swap result confirms the original has failed.
- A self-test failure means the reader electronics themselves are suspect, and only a swap with a known good unit proves that.
- The reader is connected to a control enclosure that holds mains-voltage parts.
- After replacement, the card system should be tested with real cards and the owner's programming checked.
How error code EC:27 differs from similar codes
EC:27 is one of several reader self-test codes: EC:28 is the card read test, EC:29 the memory test, EC:2A the card interface test and EC:2b the flash checksum test.
Technical reference
- Document
- Commercial Automatic Washer (Metered and Nonmetered) Troubleshooting H002C
- Edition
- Part No. 39201R9, November 2016
- Models / control
- Speed Queen/Alliance commercial automatic washers H002C: EDC (Micro-wand IIIe) models, MDC models, NetMaster models (model numbers p. 6)
- Section
- 32. EDC Error Code Listing, printed p. 59 (PDF p. 61); 41. MDC Error Code Listing, printed p. 72 (E:dr, E:FL, EC:19); 50. NetMaster Error Code Listing, printed pp. 90-93 (PDF pp. 92-95)
- Checked
- October 2026
We use the maker's document to read the code and do not reproduce it. Always confirm the complete model and control before applying these steps.
Related Speed Queen washer error codes
Is this a problem with my card?
No. EC:27 comes from the reader's own built-in write test, not from a customer card.
Can the washer run without card payments?
The manual does not say. A technician can tell you what your machine's payment setup allows.
Will it go away if I restart?
A restart may clear the display, but the manual calls the reader bad, so expect the code to come back.
Need help with Speed Queen error code EC:27?
A technician confirms the cause on site and gives you the price in writing before any work starts.