Bosch Classixx 6 - F21 Fault

[JohnnyU]

Hi Folks.

OK - As the title suggests, I'm getting an F21 fault on my Bosch Classixx 6 washing machine.  I've replaced the brushes (which were completely worn), and cleaned the rotor and stator (which were both covered in carbon dust) - however, I'm still getting the fault.  Now I don't know if it's the old fault that still needs to be reset(?), whether there's a secondary fault, or whether it was not the brushes in the first place.  The manual states F21 as 'Motor fault - contact the manufacturer'.  There doesn't appear to be a 'reset' as such (there are a few instructions given in the manual about turning the selector and holding on the spin button - but this doesn't work either) - no matter what you select on the dial, the fault F21 returns.  You get the same fault code without the motor plugged in at all.  All connections have been cleaned, so it's not that.

Any further pointers would be gratefully received.  Ideally repair pointers, as opposed to 'buy a new one' pointers...! ;)

Many thanks in advance, john.

[Whitegoodshelp (Andy)]

Hello there. When you say the brushes were completely worn that doesn't necessarily mean they were at fault. If they were at fault then at least one of them would have been charged and blackened at the point where it connects to the commutator as described and shown in this article Carbon brush diagnostics. If they were both shiny but worn they obviously needed replacing but may not have been the fault causing the F 21 error code. If one or both were charred then presumably that was the fault.

As far as I'm aware fault codes should automatically reset once the problem has been sorted. So if the fault code remains, and the manual states that F 21 is a motor fault then something is probably still wrong with the motor. Check the pins in the motor plug and the corresponding pins on the motor. The pins and connectors can become loose or out of line and when the motor plug is connected one of the male or female connectors can be pushed out of the way.

Other than doublechecking that the brushes have been fitted properly, and released from their captive transit position you need to put a continuity test meter across the appropriate pins on the motor to check continuity of the field coil, armature, and through the carbon brushes. There is also a TOC built into the windings which can potentially blow if there is excessive sparking prior to failure.