johannaweber1
Sonata Hybrid Transmission Problems
Summary of the thread
A 2015 Hyundai Sonata Hybrid is experiencing transmission issues, including unresponsive paddle shifters, rough shifting, slipping, grinding noises, and emergency mode activation. The problem is suspected to be related to the transmission control unit (TCU), a known issue in similar models. Diagnosis confirmed a defective TCU, which was replaced, resolving the transmission problems.
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4 comment(s)
johannaweber1 (community.author)
Thanks for the reply. You're right, my first guess was the TCU too, since the error code points in that direction. I was hoping it would be something simpler. Do you know if that's a common problem with the Sonata?
benbaumann1
Unfortunately, yes, I believe it is. There have been a few reports of defective TCUs causing similar issues, especially in models from that era. It definitely sounds like the control unit is the issue. You will likely need to replace it. I suggest you get it looked at by a workshop to confirm the diagnosis. I had to cough up around 1000€ for the repair myself…
johannaweber1 (community.author)
Thanks a lot for the info. I took it to the workshop, and you were right: defective TCU. Cost me about 1000€ to replace, but at least it's running smoothly now. Appreciate the help!
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HYUNDAI
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SONATA
benbaumann1
That sounds rough. I had some similar issues with my Sonata, though it's not a hybrid. Are you getting any error codes? Sounds like it could be electronic - possibly the transmission control unit. Given your symptoms, especially the emergency mode and error codes, it's definitely worth investigating the TCU. Have you done any diagnostics on it yet?