You can find this issue addressed on another site....
Due to popular request, here is more information on the E:04 problem, and some assorted tips:
If you get the E:04 error, he first thing to try is turning the washer off and back on again. You will more than likely have to begin the cycle over, but sometimes this will clear the message.
Since clogging up the drainage pipe, I have gotten that E:04 message when I've used too much laundry soap. I think that's the main reason people see that message. Just turn the washer off and start the cycle again WITHOUT adding any additional soap. I think the suds somehow make the washer think the drainage pipe is clogged.
The other thing that can happen is a genuine clog, like in the case I described in my review. The Bosch is excellently engineered to protect the pump from damage. There is a circular panel on the front of the washer that hides the drainage hose. Remove this panel (simple, but there is a knack to it) and you can pull the drainage hose out. Keep a bucket handy because the hose will be full of water. You may lose a little bit of skin off your hand during this process, and it's best if you can have the salesman demonstrate this procedure for you. That panel is not the easiest thing to remove. You have to reach in past some sharp metal to get to the drainage pipe. Wrap a towel around your hand and BE CAREFUL. It's definitely worth a shot if saving a service call is worth it to you (and clearing out clogs are NOT covered by the basic warranty). My service man assured me that removing this panel would not invalidate the warranty, but you may want to check with your dealer before you open up yours.
It's been about six months and I still adore my washer. I've found the Temp Boost setting is best for cotton towels, Delicates is great for, well, delicates, the Warm Permanent Press setting is great for jeans, and Cold Permanent Press great for most clothes. To avoid getting small items stuck between the glass and the rubber inner seal, do not overload the washer. If I try to wash too many socks, one will now and then end up in that small space. You can cram one big thing in the washer and it will still get clean (I regularly wash a bathroom carpet in there), but DO NOT cram it full of lots of little things. Follow the helpful loading instructions for each cycle.