BMW i8 Hybrid Stalling: ECU Fault or Ventilation Issue?

I experienced similar issues with my 2018 BMW i3s Hybrid at around 75,000 KM. The symptoms you're describing match what I encountered, stalling at idle and emergency mode activation. Initially, I thought it was the tank ventilation too, but it turned out the hoses were completely clogged with carbon buildup, restricting proper fuel vapor flow. During my garage visit, the technician found that the clogged hoses were causing incorrect readings in the engine control unit, triggering multiple fault codes. The fix required a thorough cleaning of the entire ventilation system and replacement of two major hoses. This wasn't a quick fix, the car was at the shop for three days due to the complexity of accessing the components in the hybrid system. This is definitely a serious issue that needs immediate attention, as continued driving could damage other components. The emergency mode is actually a protective measure to prevent engine damage. Based on my experience, you'll want a technician who's specifically certified for BMW hybrids, as these systems are quite different from conventional engines.

Thanks for sharing that experience, that's really helpful info. Mine sounds pretty much identical to what you went through, especially with those stalling issues. Quick question, do you remember roughly how much you ended up paying for the whole fix? Also, has everything been running smoothly since then, or have you noticed any other quirks pop up? Just trying to get an idea of what I might be looking at cost-wise and whether this tends to be a one-off thing or if I should be prepared for more issues down the line with my i8. Thanks again!

Hey there! Happy to give you the update on my i3s situation. After getting it fixed, I'm glad to report it's been running like a dream! The total bill came to 175 € for fixing those clogged hoses, and they also sorted out the tank ventilation valve issue while they were at it. Honestly, it was worth every penny, haven't had a single problem since the repair, which was about 8 months ago now. The car's performing way better than before, no more stalling, no more emergency mode scares, and the engine's running super smooth. The mechanic did a really thorough job cleaning out the whole ventilation system, and it seems like this was just a one-time thing. From what I understand, as long as you keep up with regular maintenance, you shouldn't have to deal with this problem again. For your i8, I reckon you might be looking at similar costs, though could be a bit different since it's a different model. But the good news is, once it's fixed properly, you should be good to go. Best investment I've made in the car so far!

Just got back from the mechanic, and I'm so relieved! You were spot on about the hose situation. Took it to a certified BMW specialist who found pretty much the same problem, clogged hoses causing all those issues. The bill came to about 200 for the complete fix, which included cleaning out the system and replacing a couple of hoses. The best part? The car's running perfectly now. No more stalling, emergency mode's gone, and the engine's purring like it should. The mechanic walked me through everything they did, which made me feel much better about the whole situation. They even showed me the gunked-up old hoses, pretty nasty stuff! Really appreciate your help on this one. You saved me from potentially spending way more at my old mechanic, who probably wouldn't have known what to look for. Think I've found my new go-to mechanic too, they really knew their stuff with these hybrids. Thanks again for pointing me in the right direction!