Renault Spider Power Steering Issue

I had similar issues with my old Saab 9-3. The vibration, spongy feel, and increased effort point to electrical gremlins more often than mechanical failures. Have you checked the simple stuff? Fuses, relays, the condition of the wiring harness to the steering pump?

Regarding your Saab 9-3, did the error manifest intermittently, and was there any correlation with temperature or humidity? Are there any specific points within the harness that are known to be problematic in similar systems?

Yes, the Saab's issue was intermittent, and it did seem worse in damp weather. I'd still advise getting it to a workshop to check the cable and plug connections of the component, as you mentioned. If it is indeed a defective cable or plug, as you suspect, it may save you time.

It was indeed a faulty connection. The repair cost was 95€. Thanks again for your time and assistance.