Learn Circuit Fu, the ancient lost art of appliance repair…

Click here to check out our structured, online appliance repair training courses for rookies and experienced techs.

FAQs | Repair Videos | Academy | Newsletter | Podcast | Contact

Stay connected with us...

Samurai on Facebook - become a fan today! Sign up for our free newsletter and keep up with all things Appliantology. Subscribe to our YouTube channel for lots of appliance repair tips and help! Follow the Samurai on Twitter and get timely morsels of Appliantological Wisdom! Subscribe to our MST Radio podcast to learn secrets of the trade.

Samurai Appliance Repair Man's Blog

  • entries
    811
  • comments
    992
  • views
    2,413,372

How to Fix All Serial Communications Error Codes in Whirlpool-built Front-load Washers

Samurai Appliance Repair Man

13,235 views

The dreaded “serial communications error” in Whirlpool-built front-load washers appears as various codes, depending on the particular model. On the Old-Skool Duet washers, the most common communications error code was F-11: communications error between the Central Control Unit (CCU) and Motor Control Unit (MCU). On the new model Duet washers, this same error has been re-labelled as F-28. On some Maytag front loaders (all built by Whirlpool, in case you didn’t already know that), you may see an F6E2 fault code, which is a communications error between the CCU and the User Interface (UI) boards.

Many a fine battle-hardened appliance warrior has been befuddled by these error codes and have needlessly soiled their undergarments throwing every control board in the box at it.

But these serial communications error codes all have one big thing in common:

They are almost NEVER caused by a bad circuit board! Instead, they are exactly as the error code description says: a COMMUNICATIONS error between two boards. In other words, a bad connection.

Oh, I know— you’ll hear some guys swear it was a bad board because they replaced the such-and-such board and it fixed the problem, so it had to be a bad board. But I’m here to show you that in 99.9999% of these cases, the board itself is perfectly functional but the real problem is the CONNECTIONS to the board.

“Uhh, howzzat, Samurai Smart-ass Guy?”

Ahh, Grasshoppah, make still your mind and the Samurai shall reveal the truth unto thee. And the truth shall make you free. Come with me now on a journey of Total Appliance Enlightenment™…

Let's think about the modern front loading washer and the average laundry room for a minute. In these front loaders, you have at least two (CCU and MCU) sometimes four (CCU, MCU, UI, and Steam Board) different boards that all need to talk to each other and pass data back and forth: digital data, voltages. How do they do this?

Since they haven’t incorporated internal Wi-Fi into appliances yet, all these boards are connected to each other by special wire harnesses called serial communications cables. All this data exchange is fact-checked and verified by a process called “handshaking” (yes, that’s what it’s really called). If, at any time during this continuous process of passing data back and forth an error is discovered during the handshaking, the CCU throws a serial communications error. The closest it can get in the error code is by telling you which two boards had trouble talking. But that’s close enough!

So what causes these handshaking errors? Lots of things! In fact, given the conditions that these washing machines have to work in— lots of vibration, moisture, humidity, heat, etc.— it’s amazing they work as well as they do. But all it takes is a loose connection at a molex connector on a wire harness or an oxidized pad on the control board to disrupt that handshaking. It doesn’t even need to be a totally broken connection, just one with low enough signal-to-noise ratio that the CCU can’t tell which is signal and which is noise.

Okay, here’s the part you’ve been waiting for: the Silver Bullet Fix for these elusive and mysterious serial communications errors in Whirlpool-built front-load washers.

The harness itself can (and usually does) check good. That's not usually the problem. The problem is at the harness connection points where the molex connector on the harness connects to the boards at either end. The tines can become loose or the pads on the board may become oxidized. Here's a technique that I've used with great success in these types of problems. BTW, all modern front loaders work the same way and use pretty much the same basic technology so this solution concept for serial communications errors applies to all brands of front load washers, not just Whirlpool:




4 Comments


Excellent video Samurai.  Have used the solder build-up many times.  Works great.

 

Do you recall this trade trick from "B-doubleE" school in the Navy:

Use a standard pencil eraser to clean the contacts on circuit boards.  It gets the copper looking like brand new.

 

Happy Thanksgiving and thank you for this awesome website !

Share this comment


Link to comment
Samurai Appliance Repair Man

Posted

Do you recall this trade trick from "B-doubleE" school in the Navy:

Use a standard pencil eraser to clean the contacts on circuit boards.  It gets the copper looking like brand new.

 

 

I remember it like it was yesterday... even though it was over 30 years ago.  I still use that trick and often tell Grasshoppers about it here at Appliantology

 

Happy Thanksgiving and thank you for this awesome website !

 

 

Happy thanksgiving back atcha, mah bruvah!  And thanks for being part this site!  

Share this comment


Link to comment
Samurai Appliance Repair Man

Posted

Domo, TAS!  Give it a shot next time you run into one of these and let me know how you make out.  

Share this comment


Link to comment