BMW 2 Series Brake Issues: Pressure Sensor Problem?

Hey there! I have some experience working on cars as a hobby mechanic. I had a very similar issue with my 2013 BMW 3 Series diesel. The symptoms you're describing sound exactly like what I experienced. In my case, it turned out the brake system wasn't properly bled after some routine maintenance. Took it to my trusted workshop and they found air bubbles in the brake lines. They did a complete brake system bleed, which solved all the issues, the warning messages disappeared, and the brakes felt firm again. Cost me around 90 Euro for the service. Could you share more details about when these symptoms started? Did this happen after any recent brake work or maintenance? Also, what specific error messages are you seeing? This would help determine if you're dealing with the same issue I had. If it's not the bleeding, the 2 Series can sometimes have issues with the brake pressure sensor, like your mechanic suggested. But I'd start with the simpler fix first.

Hi, thanks for sharing your experience! I'm actually facing these problems with my 2015 BMW 2 Series too (48273 km on the clock). The error messages started popping up about a week ago, and no recent brake work was done. My dash shows "Check Brake System" and "Drive Moderately" warnings. The symptoms you described with the air bubbles sound really similar to what I'm experiencing. I'll definitely mention this to my mechanic about checking for trapped air in the brake lines before jumping to replace the pressure sensor. Did your car also make that pumping noise from the brake system before you got it fixed? And how long did the complete brake bleeding take? Just trying to get an idea of what to expect when I take it in. The last service was actually about 2 months ago, but they didn't do any brake work then. Really appreciate your help on this!

Hey again! Thanks for the follow-up. Yeah, my car definitely had that annoying pumping noise, it was especially noticeable when I'd start the car or press the brake pedal. It would make this whirring sound, and the pump would kick in way more frequently than normal. The complete brake bleeding took about an hour at my workshop. They had to do it systematically, going through all four corners of the car. Mine had around 52,000 km when this happened, so pretty close to your mileage. You know what's interesting, even though you didn't have recent brake work, sometimes these issues can pop up if there's been any disturbance in the system. In my case, they found that a tiny leak had allowed air to creep in over time. The leak was so small it wasn't losing fluid, but just enough to let air bubbles in. Before they did the bleeding, my mechanic connected it to the diagnostic computer, and it showed similar error codes to what you're seeing. The "Drive Moderately" warning is exactly what I had too. I'd definitely get it checked soon though, even if it's just air in the lines, you don't want to risk it getting worse. My brake pedal started feeling really spongy right before I got it fixed, and that's not something you want to gamble with on these cars.

Thanks for the detailed information about your experience! Your suggestion about the systematic bleeding makes a lot of sense, especially since the symptoms match up so closely. I'll definitely get it looked at this week, don't want to risk driving around with dodgy brakes. I checked and my brake fluid level is normal, but what you mentioned about that tiny leak letting air in without losing fluid is really interesting. That could explain why this started happening without any obvious cause. I'll make sure to ask my mechanic to run a full diagnostic before jumping to conclusions about the pressure sensor. If it's just trapped air like in your case, that would be a much simpler fix than replacing parts. Really appreciate you taking the time to share your experience, it's given me a much better idea of what might be going on and what to expect at the workshop. Will update once I get it sorted out!