BMW 6 Brake Warning: Low Fluid or Bigger Problem?

Hi! I have some experience working on cars and had a similar issue with my 2019 BMW 5 Series diesel. When my brake warning light came on, I also noticed the pedal felt spongy. Took it to my trusted mechanic who found worn brake pads and rotors. The brake fluid was low because the pads were really worn down. Total repair cost me around 480 Euro, but it fixed the problem completely. Before giving more specific advice, could you share: How many miles/kilometers on your car? Are you hearing any squealing when braking? Did this start suddenly or gradually? I had good experience with the 4 Series too, but brake wear can vary a lot between models. Let me know these details and I can share more about what to look out for.

Thanks for sharing your experience! Mine is currently at 144792 KM and just had its service last month. In my case, I'm not hearing any squealing, but the warning appeared quite suddenly during my morning drive. The pedal definitely feels different, kind of soft and spongy like you mentioned. Good to know about the worn pads being a potential cause. I'll probably get it checked soon, just wanted to get some real-world experiences first before heading to the workshop. Did your mechanic mention any other common issues to watch out for with these brakes?

Hey again! Thanks for those details. Yeah, that sounds really similar to what I experienced with my 5 Series. Mine was at around 130,000 KM when it happened, so pretty close to your mileage. Since you mentioned having service last month, it's a bit strange they didn't catch any brake wear issues then. When I had my problem, my mechanic actually pointed out that BMWs can sometimes wear brake pads unevenly, the outer edges might look fine during a quick check, but the inner parts could be pretty worn down. In my case, beyond the worn pads and rotors, my mechanic also found that one of the brake caliper pistons was slightly sticky, which contributed to the uneven wear. That's something worth having them check out. The spongy pedal feel usually means air in the system or low fluid, but in our cars, it can also indicate a failing master cylinder, though that wasn't my problem. Since you're not hearing any squealing (I didn't either), it might be different from my situation. But given the sudden warning and that spongy pedal feel, I'd definitely get it checked soon. These symptoms shouldn't be ignored, even if it turns out to be something minor like in my case. Want me to share what specific tests my mechanic ran to diagnose the problem? Might help you know what to expect when you take it in.

Thanks so much for all that detailed info! That's really helpful, especially about the uneven brake pad wear and the caliper pistons, definitely wasn't aware of those potential issues. It is weird that the recent service didn't catch anything, but maybe it developed quickly. I actually just booked it in for tomorrow morning, figured better safe than sorry with brakes! Would love to hear about those specific tests your mechanic ran. The more I know going in, the better I can understand what they're checking for. This is my first BMW, so still learning all its quirks. Really appreciate you taking the time to share your experience, it's made me feel a lot more confident about what might be going on with mine.