BMW Z4 Won't Start: Key Symbol Mystery Needs Solving

Hey there! Had a similar issue with my 2005 BMW Z3 last summer. That key symbol is definitely familiar, mine turned out to be more than just the key sensor. The control unit was completely shot and needed replacement. The symptoms were exactly like yours, key symbol on dash, no start, complete silence when turning the key. Initially thought it was just the key, but the diagnostic at the shop revealed the whole control unit was fried. Not a quick fix, had to wait for parts and the car was at the garage for three days. It's definitely a serious issue that needs proper diagnosis, don't try any DIY fixes as you might end up damaging other components. My advice would be to get it to a specialized BMW workshop. They have the right diagnostic tools to pinpoint whether it's just the Hall sensor or something bigger like in my case. Mine's running fine now after the repair, but you'll want to get this checked soon to avoid any additional complications.

Thanks for sharing your experience! Really helpful to hear about a similar case. Just curious, do you remember roughly how much the control unit replacement set you back? And has everything been working smoothly since the repair? I'm trying to get a ballpark figure before heading to the shop, and it's good to know what to expect long-term.

Hey again! Happy to help out with those details. After seeing my mechanic, they confirmed it was indeed the Hall sensor in the ignition key that was acting up, but like in my case, the control unit needed replacing too. The total bill came to around 1000 € for the whole job, definitely not cheap, but worth every penny considering how essential it is to actually get the car running! The good news is that everything's been working perfectly since the repair. No more annoying key symbol, no starting issues, just smooth sailing. It's been such a relief not having to worry every time I turn the key. I know it might seem like a steep price, but honestly, with these older BMW models, sometimes you just have to bite the bullet and get things fixed properly. Trust me, once you get it sorted, you'll feel much better. These control units are pretty reliable once replaced, so you shouldn't have to deal with this particular issue again. Let me know how it goes when you get it checked out!

Thanks so much for the detailed info! Just got back from the mechanic and wanted to update you. You were spot on, it was a similar issue to yours. Took it to a specialized shop that had great reviews, and they diagnosed both the Hall sensor and control unit problems right away. The whole repair came to about 950 €, pretty close to what you paid. The funny part was when the mechanic started explaining everything, I felt so much more confident knowing what he was talking about thanks to your earlier messages. Even caught him looking impressed when I mentioned the control unit! The car's running like a dream now. Such a relief to turn the key and have it start right up without seeing that annoying symbol. Really appreciate you taking the time to share your experience, saved me a lot of worry and probably some cash too, since I knew what to expect. Definitely the right call to get it properly fixed rather than trying cheaper alternatives.