How to fix Smeg Induction Cooker SIHP274B?

When switching on the Smeg Induction Cooker SIHP274B it now intermittently flashes the control panel, makes some strange magentic noises, comes up with Error E r 2 2 on the control panel then switches itself off. This happens 50% of the time. At other times it works perfectly. I would like to know what E r 2 2 means please and how to fix it. Repair man came out and told us to buy another type of cooker but it was expensive and has only been installed for 6 months!