BMW iX Brake System Warning: Pump & Power Issues

Hi there! I had a similar issue with my 2021 BMW i4 (also own an iX3). I have some experience working with EVs, but I mainly trust my workshop for complex issues. When I faced those exact symptoms, the warning light, reduced braking power, and that annoying pump noise, it turned out the brake system wasn't bled properly during a routine maintenance. The workshop had to do a complete brake system bleed to fix it. Cost me around 90 Euro, but the problem was solved immediately. Before jumping to conclusions about the pressure sensor, could you share: How long has this been happening? Did it start after any recent maintenance work? Are you experiencing any vibrations when braking? This info would help narrow down if you're facing the same issue I had.

Thanks for sharing your experience! I've had my iX since new (194112 KM on the clock), and this issue just popped up three days ago without any prior maintenance work. Actually, I'm not feeling any vibrations while braking, but the pump noise is definitely getting more frequent and louder, especially when I first start driving. Your bleeding issue story is interesting, makes me wonder if air somehow got into the system. I'll definitely mention this to my service advisor when I bring it in. The reduced braking power is making me a bit nervous, so I've already booked it in for next week. Good to know it might be something relatively straightforward like yours was!

Hey again! Just wanted to follow up on your latest response. You know, after reading your description of the timing and symptoms, I'm starting to think your case might be different from my bleeding issue. In my experience with both BMWs, when air gets in the system, it usually happens right after service work, which isn't your case. Given that it started suddenly and you've got the combination of pump noise, reduced braking, and warning lights without any recent maintenance, I'm leaning more toward my initial thought about the pressure sensor. Looking back, I actually had a similar sudden onset of symptoms in my i4 about a year before the bleeding incident, and that time it WAS the pressure sensor. The pump noise getting louder at startup is particularly familiar. The sensor replacement cost me about 400 Euro including labor, but it fixed everything immediately. Much better than leaving it and risking more serious brake issues. Smart move booking it in quickly, these brake issues aren't something to mess around with. Would you mind updating us after your workshop visit? I'm really curious to know if it turns out to be the same sensor issue I had. Stay safe until then!

Thanks so much for the detailed follow-up! You've actually made me feel a lot better about this whole situation. The fact that you've experienced both issues, the bleeding problem and the pressure sensor, really helps put things in perspective. You're right, since I haven't had any recent maintenance work, the pressure sensor theory makes more sense. The symptoms match up exactly with what you described, especially that startup pump noise. It's good to know the repair cost isn't astronomical either. 400 for a sensor replacement isn't cheap, but it's definitely better than what I was imagining! I've made note of all this to discuss with my service advisor next week. And yes, I'll definitely update the thread once I get the diagnosis and repair done. Really appreciate you taking the time to share your experiences, it's super helpful having insight from someone who's been through similar issues with these cars. Will keep you posted on what they find!