Sienna transmission issues

My 2015 Toyota Sienna with a gasoline engine has a weird transmission issue. With 152984 km, the paddle shifters are unresponsive, shifting is rough, and I hear grinding during gear changes. The gearbox seems stuck in emergency mode, and the diagnostic tool shows an error. Anyone else faced this? I suspect a defective control unit.

4 comment(s)

Hey, I drive a Sienna too, and this sounds like what I went through last year. Does the error code point to the transmission control module? Mine caused similar shifting problems and put the transmission into limp mode. Get it checked out.

Thanks! My OBD2 scanner shows multiple codes pointing to the TCM. Could you share more details? Did you replace the entire transmission, or just the control module? How much did it cost?

Yep, it was the TCM. Luckily, I didn't need a whole new transmission, just the control module. Take it to a trusted workshop and have them diagnose it properly. It sounds like the TCM, and driving it like that could cause more damage.

Thanks so much for the advice! The mechanics confirmed the transmission control unit was faulty and needed replacement. The repair cost me around 1000€, but my Sienna is shifting smoothly again. I appreciate your guidance!

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