X5 Brake Issues: Pump Noise and Weak Performance

Hey there! I have some experience working on BMWs and had a similar issue with my 2019 X3. The symptoms you're describing sound familiar. I took my car to the workshop when I noticed poor braking performance and those annoying error messages. Turned out the brake system wasn't properly bled, which caused air to get trapped in the lines. The mechanic had to do a complete brake system bleed using their diagnostic equipment. Cost me around 90 Euro, but it fixed the issue completely. Before you jump to conclusions about the brake booster sensor though, could you share: When did these symptoms start? Does the brake pedal feel spongy? Have you had any recent brake work done? This way I can better understand if your issue is similar to what I experienced.

Hey, thanks for sharing your experience! I've got similar symptoms with my X5 (123893 KM on the clock). The brake pedal does feel a bit spongy, and these issues started about a week after my latest service. No recent brake work though, besides regular maintenance. Your suggestion about air in the brake lines makes sense, that could explain both the weak performance and the pump behavior I'm experiencing. Definitely worth checking out before assuming it's a sensor issue. Would you mind sharing which diagnostic equipment your mechanic used for the bleeding process? I'd like to mention that specifically when I take it to the workshop.

Hey again! Glad I could help point you in the right direction. Yes, the symptoms you're describing, especially that spongy brake pedal, sound exactly like what I dealt with. And since you mentioned it started after a service, that's an even bigger clue. Sometimes during routine maintenance, air can accidentally get into the system. In my case, the mechanic used the BMW ISTA diagnostic system for the bleeding process. It's pretty crucial for these modern BMWs because of their complex brake systems. My mechanic explained that you can't just do a manual bleed like on older cars, these systems need the computer to cycle through different modes during bleeding. I remember being worried about my X3's brake booster sensor too, but the proper bleeding sorted everything out. The pump noise went away completely, and my brake pedal got back that nice, firm feel. Quick tip though, make sure to mention to your mechanic that the issues started after the service. They might even cover the cost since it could be related to their previous work. That's what happened in my case actually, didn't end up paying anything since it was traced back to the service. Let me know how it goes when you get it checked out. Always interested to hear if others have the same fix work for them!

Thanks so much for all the detailed info! Really helpful to know about the BMW ISTA diagnostic system, I'll definitely bring that up with my mechanic. It's actually a relief to hear this might just be an air-in-the-lines issue rather than something more serious with the sensor. I'll give my regular workshop a call tomorrow and mention how the problems started right after the service. Good point about possibly getting it covered, hadn't even thought about that! I've been using them for years so hopefully they'll be understanding about it. Really appreciate you taking the time to share your experience. I was getting worried about potentially expensive repairs, but this sounds much more manageable. I'll update you once I get it sorted. Thanks again for helping me narrow down the problem!