BMW i3 Key Fob Failure Leaves Drivers Stranded

I had a similar issue with my 2016 BMW i8 Hybrid last month. The symptoms matched yours exactly, key symbol on dash and wouldn't start. Initially thought it was just a dead key fob battery, but the diagnostic showed "Affected control unit defective" error code. Took it to the garage where they found the key recognition system had failed. My case required replacing the key reader module and reprogramming the vehicle access system. Not a quick fix, car was in the shop for three days due to the complexity of the hybrid system integration. This isn't just a basic sensor issue, it's tied into the car's immobilizer system, which is why it prevents starting. If you're getting the same error code, it's likely the same problem. Would definitely recommend getting it checked soon as it's a critical security component.

Thanks for sharing your experience with the key system problem! That's really helpful to know about the key reader module being the culprit. Quick question, do you remember roughly how much you ended up paying for the whole repair? Also, has everything been working smoothly since they fixed it? Been debating whether to take mine to the dealer or find a specialized hybrid shop.

Hey there! Just wanted to follow up about the repair costs and results. I paid exactly 1000 € to get everything sorted out, which included replacing the defective control unit. And I'm happy to report that since getting it fixed, my i8 has been running perfectly, no more annoying key symbols or starting issues! The Hall sensor in the ignition key was indeed the problem, just like I suspected. To answer your question about dealer vs. specialized shop, honestly, given how complex these hybrid systems are and how the key recognition is tied into multiple security systems, I'd probably recommend going with someone who really knows these specific models. I went with a certified BMW specialist and don't regret it one bit. The car's been running like a dream for the past few weeks, and I haven't had a single problem with the key system since the repair. Trust me, it's worth getting it sorted properly, these kinds of issues only get worse if you leave them too long. Best of luck with yours!

Thanks for the detailed response! I took your advice and got my car fixed at a certified BMW specialist last week. You were right, it did end up being a complex issue with the key recognition system. My repair actually cost a bit more, around 1200 €, since they had to reprogram a few additional components. The funny part was when I went to pick up my car, they showed me the old control unit and it was completely fried! No wonder I was having those starting problems. The mechanic was super thorough and even gave me some tips about maintaining the hybrid system. I've driven it for about a week now and everything's working perfectly, no more key symbols or error codes. Really glad I didn't try to cut corners with a cheaper repair shop. Thanks again for steering me in the right direction with this! It's such a relief to have it sorted properly.