BMW M4 Power Steering Failure: Warning Signs & Solutions

Hey there! I had a really similar issue with my 2014 BMW M3. The symptoms were almost identical, steering got super heavy and that annoying vibration was driving me crazy. Took it to my regular workshop and turns out it was just a faulty wiring connection to the power steering unit. The mechanic found some corroded cables and a loose connector. They replaced the wiring harness and reconnected everything properly, cost me 95 Euro total. After that, steering was smooth as butter again. If it helps, I also had an older 3-Series that was pretty reliable, but these electrical gremlins do pop up sometimes. Could you share if you've checked the power steering fluid level or noticed any unusual noises before this started happening? Also, it'd be helpful to know which error code you're getting, might help narrow down if it's the same issue I had. Hope this helps!

Thanks for sharing your experience! My M4 currently has 119608 KM and just had its service last month. I'm getting a similar vibration issue but also noticing a slight whining noise when turning at low speeds. Haven't checked the fluid levels yet, definitely will do that first before heading to the workshop. Could you elaborate on how long your repair took? Just trying to figure out if I need to arrange alternative transport. Also good to know about the wiring harness, will mention that when I take it in.

Hey again! Yes, I definitely remember having that whining noise too in my M4, it's almost like a grinding sound when turning, right? Looking back, I should have mentioned that in my first reply. In my case, the repair took about 4-5 hours. They needed some extra time to properly diagnose and trace all the wiring connections. I dropped it off in the morning and picked it up late afternoon. Definitely arrange backup transport just to be safe. The fluid level check is a good start, though in my case it wasn't the issue. Since you're at 119K KM, it could also be wear and tear on the electrical connections, just like what happened to mine. These performance BMWs are sensitive to electrical issues, especially in the steering system. Quick tip: when you take it in, ask them to check the connectors near the steering rack specifically. That's where they found my problem. The corrosion wasn't visible from the outside, but once they opened it up, it was pretty obvious. Keep us posted on what you find out, might help other M4 owners down the line!

Thanks so much for the detailed follow-up! Really helpful to know about the repair timeframe, I'll definitely arrange a backup car for the day. That grinding noise you mentioned is exactly what I'm experiencing! It's actually gotten a bit louder over the past few days, so I've booked it in for next week. I just checked the power steering fluid and surprisingly, it's at the right level. I'm betting more and more that it's the same electrical issue you had. I'll make sure to mention the steering rack connectors to the mechanic and have them take a closer look there. The 4-5 hour timeframe actually works perfectly with my schedule. Really appreciate you taking the time to share your experience, definitely made me feel better about the whole situation. I'll try to remember to post an update once I get it sorted out. Thanks again for all the help!