It doesn’t happen every time but sometimes when I start my car the power steering light comes up saying it has failed and then all I do it turn it off and turn it back on and the power steering works again, does anyone have any idea why it’s happening? And is it a long term problem? And how can I fix it? Thanks.
Typically the first port of call for this on the Mk3 Ibiza is actually the battery - the Power Assisted Steering (PAS) pump is quite a big draw on these and they can throw the light for this. If you battery is old or otherwise showing signs of weakness that would be a good place to start.
The fact that it seems to clear on a quick restart leans me against this in your case though - the battery is going to be weaker the second time around as unless you've driven it a bit the alternator won't have had time to replenish the initial effort of starting.
A known fault on these that causes the PAS light to be lit is the 50A fuse for the PAS pump - they have a tendency to crack which causes an intermittent connection and this leads to the light.
If neither of these things then it might be the pump itself - they are electric and sometimes suffer from water ingress at the connectors causing intermittent electrical faults.
Another possibility is the steering angle sensor, an outside bet though.