Peugeot iOn spongy brake pedal

That's interesting. I had a similar thing happen with my old Renault Megane, though mine was a petrol engine. Low brake fluid and soft pedal. I initially thought it was a leak too, but it turned out the brake pads were just super worn. As they wore down, the fluid level dropped as the calipers had to extend further. Have you checked your pad thickness?

Hmm, I hadn't really thought about the pads themselves. I glanced at them, and they didn't look completely gone, but maybe they're thinner than I realized. If it was the pads, wouldn't I hear some squealing or grinding? Or is it possible for the fluid to drop noticeably without those noises?

It's definitely possible! The noises don't always start right away, especially if you mostly do city driving. The fluid drop can be gradual. With my Megane, I only started hearing a slight squeal right before I took it in. Honestly, with those symptoms and the mileage on your iOn (204500 km is quite a bit!), I'd get a proper brake inspection done. Could be worn pads, or maybe even something like a slightly leaky brake line that's hard to spot. Better safe than sorry with brakes!

You're right, safety first. I took it to a workshop, and you nailed it – the front pads were worn down pretty badly. Replaced the pads and topped up the fluid. Cost me 480€ all in. Pedal feels normal again. Thanks for pointing me in the right direction!