BMW i4 Alarm System Dead: Anti-Theft Warning Signs

Hey there! I actually had a similar issue with my 2018 BMW iX3. The alarm system completely failed last month, showing the same symptoms, no activation and dead interior sensors. Took it to a certified BMW technician and turned out the main control module for the anti-theft system had failed. They had to replace the module and recode the entire alarm system to sync with the car's central locking. The repair wasn't super complicated, but it needed specialized diagnostic equipment to properly code the new module. The fix required about 4-5 hours of work, including testing all sensors and making sure the optical indicators (turn signals) were properly synced with the locking system. It wasn't a serious mechanical issue, but definitely not something you'd want to leave unattended since it's a security concern. I'd strongly recommend going to a certified BMW dealer or a specialized EV technician who has experience with BMW's security systems. These newer electric models have integrated systems that need proper coding equipment and expertise.

Thanks for sharing your experience! Glad you got it sorted. I've made an appointment with a certified BMW dealer next week since it sounds like the same issue I'm having. Just curious, do you remember roughly how much you ended up paying for the whole repair? Also, has everything been working smoothly since the fix, or have you noticed any other quirks with the system?

Hey again! Just wanted to update you on my repair costs and experience. The total bill came to 45 € for fixing the alarm system, which was honestly less than I expected. They coded it to properly activate with the optical locking signals (you know, when the turn signals flash when you lock/unlock). Everything's been working perfectly since the fix, no more alarm issues at all. The interior sensors are responding correctly, and the whole system activates exactly as it should when I lock the car. It's such a relief not having to worry about whether my security system is actually working or not! My iX3's been running great otherwise, no other quirks with any of the systems. Definitely made the right choice going to a certified tech. These modern BMWs really need someone who knows their stuff when it comes to the security systems. Hope your appointment goes just as smoothly as mine did! Let me know how it works out for you, always interested to hear if others are experiencing the same fixes on their BMWs.

Thanks for all that detailed info! I finally got my car back from the mechanic yesterday, and I'm really glad I followed your advice. The whole experience was actually much better than I expected. The issue was exactly what you described, a faulty control module. They replaced it, recoded everything, and now my alarm system is working perfectly. The interior sensors are responding, and I love seeing those turn signals flash when I lock the car again. The total cost was a bit higher than yours at 580, but they also found and fixed a small wiring issue while they were at it. Worth every penny for the peace of mind, honestly. The car feels like new again. Really appreciate you sharing your experience, it gave me the confidence to get this sorted properly instead of trying cheaper alternatives. These BMWs definitely need proper care from people who know what they're doing! Thanks again for all your help.