how can I fix my Zanussi Jetstream Turbodry 1200 WJS 1265W?

My washing machine above is displaying E90 at the start of every wash. I have to repeatedly press the start button to erase the E90 but it's getting really bad now and I can't leave it and go out! My husband thinks it may be a bad connection somewhere. Please could you give me some advice on what to look for when he takes the case off the machine? Many thanks. Joanna Carey email address: rt.jmcarey@gmail.com