Klasse power steering failure

A vibrating steering wheel and increased steering effort do indeed suggest a power steering issue. I have experienced similar symptoms on my C Klasse. Before condemning the steering rack, I would suggest inspecting the power steering system. Is your vehicle equipped with electric steering or a hydraulic system? Have you checked the hydraulic fluid level if applicable? A defective cable or plug connection could plausibly cause your symptoms.

Good point about the hydraulic fluid, I'll check that. It's got electric steering, so where exactly should I be poking around for these 'dodgy connections' you mentioned? Any specific spots that are known to cause trouble? I am quite sure the error code points to the power steering unit.

Given that your vehicle utilizes electric power steering and you are observing a fault code related to the power steering unit itself, it is prudent to suspect a malfunction within the electric steering system. Visual inspection of accessible wiring and connections may reveal obvious damage. However, diagnosis within the electric steering system often necessitates specialized diagnostic equipment. Therefore, proceeding to a qualified workshop is advisable for comprehensive evaluation and repair.

Thanks for the advice. Turns out you were spot on about the connection! Took it to the shop, they wiggled some wires, charged me 95€ and now it's fixed. They confirmed it was a faulty connector on the steering system. Back to smooth sailing!