Electric power steering failing

I’ve got a 2010 corsa ecoflex. Soon after I bought it (Oct 2018) the power steering kept intermittently failing. Took it to the garage and was quoted about £1500 to change to entire power steering column- the mechanic also said he couldn’t find an issue so he was kind of guessing the best move. Spring this year there have been no issues at all however last week it started again. This makes me think that it could be weather related? (It has been very wet recently - although I can’t remember if it was wet when it happened before)
I know 0 about cars but would like to exhaust my options before spending a large amount either fixing or buying a new car.
I have found a lot about a belt slipping in wet weather but only in reference to old school power steering rather than electric.
Anyone got any ideas?

The Vauxhall/Opel Corsa was not sold in The US, and this is a US-centric forum, so I doubt if anyone here is likely to have practical experience with that model.

That being said, GM did issue Technical Service Bulletins in The US in regard to problematic electric power steering on some of their US-built models, so I would suggest asking the local dealership if any TSBs were issued in Europe for your vehicle.

You have the power assist motor on the column and not the rack. Saginaw Steering Gear’s screwy solution instead of designing an electric rack.

It could be the motor itself, it could be a sensor. A mechanic with a scanner can plug into the car and watch for this. Apparently you need a better mechanic than you have. Well worth paying the tech for his time to clearly diagnose the problem.

Thank you!

They did use a scanner, but there were no faults registering. This is why he couldn’t work out what the issue was

Where does it say that?

Well, the mechanic at the garage told me he had (maybe naive to believe him) and my brother (also a mechanic and trained motorsport engineer) also used a scanner and no faults registered.

But you didn’t tell US. It is not in your original post.

Scanning for faults while the car sits is not the same thing as riding in the car while watching the steering system inputs and outputs on the scanner looking for problems.