MarkX steering vibration spongy handling

Based on the symptoms, it appears there is a malfunction within the electric power steering system. The vibrating steering wheel, spongy handling, error message within the ECU, and increased effort required for steering are all indicative of a potential fault within the electrical components governing the steering assist mechanism. Before we delve deeper, may I ask the current mileage of your vehicle, and whether you have observed any fluid leaks near the steering rack?

Mileage is 131655 km. No leaks that I can see. What electrical components are we talking about?

Thanks for the info. Considering the absence of any fluid leakage, it is probable that the issue lies within the electrical domain of the steering system, specifically a defective cable or plug connection. While a comprehensive diagnosis would necessitate a thorough inspection of the steering system's electrical architecture, I strongly recommend a visit to a qualified automotive workshop, as the error memory is already indicating a problem. Do not delay to prevent further wear and tear to the steering system.

Thanks for the advice! Took it to a shop and you were right, it was a defective plug. Cost me 95€ to fix. Appreciate the help!