Freestar belt handover malfunction

Yep, sounds like the tensioner. How many kilometers are on it? And when was the serpentine belt last changed?

Thanks! It's got about 173948 km. I'm not sure when the serpentine belt was last replaced. Could a worn serpentine belt cause the tensioner to fail?

A worn belt can cause extra stress on the tensioner, but at that mileage, the tensioner itself is likely the problem. Honestly, you're probably looking at a replacement. I'd suggest taking it to a workshop.

Thanks so much for the confirmation and advice. I took it to a workshop like you said. You were right; the belt tensioner was defective. The total repair cost was 455€. Thanks again!