BMW i8 Hybrid Transmission Issues, Seeking Repair Tips

Hey there! I had a somewhat similar issue with my 2016 BMW i3. As someone with some experience working on hybrids, I can relate to your transmission concerns. When my car started showing weird shifting patterns and warning lights, I initially panicked too. Took it to my trusted workshop, and it turned out to be an undervoltage problem affecting the transmission control unit. The fix cost me about 240 Euro, but it sorted everything out. The symptoms were exactly like yours, erratic shifting and emergency mode activation. Before jumping to conclusions about the transmission fluid, could you tell me if you've noticed any other warning lights or battery-related issues? Also, when was the last time you had a full diagnostic scan done? Knowing these details would help me share more relevant info from my experience. The i8 and i3 share some similar hybrid components, though they're quite different beasts overall. Let me know those details, and I'll try to help further!

Thanks for sharing your experience! My i8 just had its service about 2 months ago at 100,735 km, and everything was supposedly checked out fine then. Haven't noticed any battery warning lights, just the transmission warning. I did a basic scan with my OBD reader but it only showed generic transmission-related codes. Interesting that you mention the undervoltage issue, I've been running in Sport mode more often lately, which might be relevant? The shifting problems seem worse when switching between electric and gas modes. Maybe I should get the voltage levels checked before diving into transmission fluid changes. Would you recommend taking it to a hybrid specialist rather than a general BMW shop? Getting a bit anxious about this since these transmission repairs can get pretty costly.

Hey again! Yeah, I totally get your concern about those repair costs. When I had my i3, I learned that Sport mode usage usually isn't directly related to these transmission issues, but the electric-to-gas mode switching problems definitely ring a bell. That's exactly what I experienced before discovering my undervoltage problem. In my case, I first went to a regular BMW dealer who couldn't quite pinpoint the issue. They kept focusing on the transmission fluid, which would've been an expensive fix for no reason. I then found this specialist hybrid workshop, absolute game changer. These guys actually understood the complex interaction between the electric and conventional systems. Given your symptoms are so similar to what I faced, especially that mode-switching trouble, I'd definitely recommend going straight to a hybrid specialist. The basic OBD codes can be misleading with these cars, my scanner showed generic transmission codes too, but the real issue was way more specific to the hybrid system. The good news is that if it's the same undervoltage problem I had, it's not nearly as expensive as a full transmission repair. Still, get it checked soon, I learned the hard way that these symptoms don't improve on their own. Let me know what the specialist finds, really curious if it's the same issue I had!

Thanks everyone for the helpful responses! Just wanted to update you, I took your advice and found a hybrid specialist workshop. They ran a complete diagnostic and you were right, it wasn't actually a transmission fluid issue at all! Turns out there was a voltage regulation problem affecting the transmission control unit, pretty similar to what you experienced with your i3. The repair cost wasn't nearly as bad as I feared, around €300 for the fix. They also checked all the hybrid components while they were at it, which gave me good peace of mind. The car's running perfectly now, no more erratic shifting or warning lights, and the mode switching between electric and gas is smooth again. Really glad I asked here before going to a regular BMW shop that might've pushed for unnecessary transmission work. Thanks again for steering me in the right direction! This could've been a much more expensive repair if I'd gone with my initial assumption about the transmission fluid.