E90 shows up on zanmussi
This error code seems to be the control board detecting a wrong configuration (in other words, an illogical set of sensing conditions, from its connected sensors and wiring). It apparently can happen, when wires become badly contacting, or if contaminated with motor brush carbon (the horrible black powder that comes off the motor commutator and brushes), or corroded from other contaminants from the soap dispenser area. You should be able to check this, remove, clean and replace the contacts:
Take the top off the machine, (ENSURE IT IS UNPLUGGED) andon the right hand side of the machine, you should see a set of 4 blue wires that go from the electronics module to the front display unit. Take this plug off (it is held on by plastic retainers) clean with wd40, or silicone (Servisol) contact cleaner, then dry, replace, then try again. If it is very badly corroded or pitted, you may have to replace that part of the wiring and socket.
If it is not that, then the wiring to/from various other sensors could be damaged, or the control board could be faulty. It is probably worth checking around other plugs and sockets, re-seating each one in turn, that lead to the control board, before calling an engineer in, or getting a spare board, as they are expensive (£60 - £80). Pulling off and plugging back on (Re-seating) the plugs and sockets has the effect of cleaning the contacts, and may fix certain intermittent faults like this. Obviously check for any plugs/sockets that appear burnt, corroded, or discoloured compared with the others, and clean the contacts with emery or a needle file. Hope this helped
