Mercedes B Klasse tire pressure ABS and steering problems

The symptoms you describe, particularly the ABS light and steering issues alongside the low tire pressure, do suggest a significant problem. A defective valve in the tire could be the culprit, leading to a rapid loss of pressure and triggering those other warnings. I recall experiencing similar issues, although on a slightly older model. Have you inspected the tire itself for any visible damage, such as a nail or cut? Sometimes a small puncture can be difficult to spot initially.

I did a quick look but didn't see anything obvious like a nail. Is it possible a slow leak could cause all these issues? I'm wondering if it's worth just topping off the air and seeing if it happens again, or if I should take it straight to a shop. What did you do when you had the same issue?

While topping off the air might temporarily resolve the low tire pressure warning, it won't address the underlying cause, and the associated ABS and steering problems are concerning. In my case, the tire appeared visually fine, but the valve stem was indeed faulty, causing a gradual but significant air leak, which the car's systems interpreted as a more serious issue. Given the potential for further complications with the ABS and power steering, I'd advise against prolonged driving and recommend a professional inspection at a workshop. They will be able to identify the cause of the leak and fix it.

Thanks a lot for the advice! Took it to the shop, and you were spot on. Turns out it was a defective valve in the tire causing a slow leak. New valve and everything's back to normal. Total cost was around 280€. Appreciate the help!