People say it can come from bugs in the machine because of constant cooler washes - they say (I have never done it) run the machine empty on the hottest wash cycle with a cup of vinegar in it - to kill off the accumulated bugs.
When we had a smell in our machine it was coming from foul water in a blocked drain. Sniff the pipe that runs off to the drainage system to be sure.
Good luck...
Peccavi
September 2010
Automatic Answer
We may have found other answers which could help you.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix washing machines.