BMW 3-Series Key Symbol Issue: EWS System Failure Help

Hey there! I had a similar issue with my '98 BMW 5 Series (previous car was a 3 Series too). I've got some experience working on cars, mainly basic maintenance stuff. Dealt with exactly the same symptoms, key symbol lighting up and starting problems. Took it to my trusted workshop and it turned out to be a defective EWS control unit (electronic immobilizer system). The repair set me back about 1000 Euro, but it fixed the problem completely. Before you jump to conclusions about the Hall sensor though, could you share: Does the engine crank at all? Any other warning lights? Have you tried using your spare key? This info would help narrow down if you're facing the same issue I had.

Thanks for the detailed response! My car has 50698 KM on the clock and was just serviced last month. The engine does crank but stops immediately. No other warning lights except that annoying key symbol. I've actually tried both keys with the same result. Even tried changing the battery in the key fob thinking that might be it, but no luck. I was hoping it wouldn't be the EWS unit since that's pretty expensive to replace. Might have to bite the bullet and get it checked by a professional. Could you share which diagnostic tools your mechanic used to confirm it was the EWS? Just want to make sure they do a thorough check when I take it in.

Hey again! Thanks for the follow-up info. Those symptoms sound exactly like what I experienced with my BMW. My car had about 45000 KM when it happened, so pretty similar mileage to yours. The mechanic used a professional BMW diagnostic system to pinpoint the EWS issue. They first checked the key's transponder communication with their tester, then moved on to testing the EWS unit itself. The diagnostic showed the EWS wasn't properly communicating with the keys anymore, even though both keys were physically fine. I initially hoped it would be something simpler too, trust me, I wasn't thrilled about the repair cost! But after getting it fixed, the car has been running perfectly for the past two years. No starting issues or warning lights since. Quick tip though, while you're getting it checked, have them look at the key reader ring around the ignition cylinder too. Sometimes that can cause similar symptoms and it's a much cheaper fix. My mechanic checked that first before diving into the EWS replacement. Let me know how it goes when you get it checked out. Fingers crossed it's something less expensive than what I dealt with!

Thanks so much for all this helpful information! Really appreciate you taking the time to explain everything in detail. That's a great tip about checking the key reader ring, I hadn't even thought about that possibility. I've just booked an appointment with a BMW specialist for next week, and I'll definitely mention both the EWS unit and the key reader ring to them. It's actually reassuring to hear that your car has been running perfectly for two years after the fix. Even though the potential cost is making me nervous, at least I know there's likely a proper solution. I'll make sure they use their diagnostic system to thoroughly check everything before replacing any parts. I'll probably post an update once I get it sorted out, might help other BMW owners dealing with similar issues. Thanks again for sharing your experience!