Hello,
I didn't get a chance to read through the whole thread about error code F-28.
Our machine started to show F-28 after 4 years of extensive use but now the code became annoying, we couldn't do full a cycle without the code showing up.
To fix it, I took off the top and back covers, grabbed a small tube of dielectric grease (the lube, not the spray) and carefully removed all the connections in my sight of view, ccu, mcu etc. everything that I could reach and take apart, put a bit of dielectric on each connectors and put them back in
The ccu connections/harnesess were the trickiest to do 'cause they have so many small connections so close to each other so with the help of a needle I've put just a small dielectric lube on top of each metal connector inside the connections. A well lit environment and firm hands will help.
In my opinion it's a bad way they've designed the ccu, mcu connections, all those connectors have to touch the copper on circuit board but through time these connection can become loose.
On the warning side: if you put too much dielectric on the ccu connectors so two adjacent wires inside the connector short circuit each other through the lube you can fry the board. It sounds like a DIY but if you've never had to deal with electric connections through your life ask somebody more experienced.

http://www.permatex.com/products/Aut...ric_Grease.htm

P.S. Beside the above issue we're happy owners of the four years old Kenmore HE2t. I have to mention that one year ago I had to tighten the screws of one of the panels, the screws became loose and it was making an awful noise while spinning and shaking.

Toronto, Ontario, Canada