The cost to fix this is way lower than what some people are quoting. It shouldn’t be anywhere near $2K.
I just fixed the same issue on my 2019 model. The sliding door cable replacement was about $50-$60 on Amazon. It took me around 2 hours to fix it after watching a YouTube tutorial.
It’s a $178 part online. You can fix it with a 10mm socket and a flat screwdriver. My neighbor had the same issue, and it only took me 25 minutes to fix.
I was quoted $1,500 by a shop, but I got the part for $50 and spent the day replacing it myself.
I had the same issue with my 2011 Sienna. The part is pretty cheap. I think it was about CA$350 per side at the dealership to fix it.
For DIY, fixing this involves a new door motor, cable, connectors, and some disassembly. It’s not an easy fix, so I’d suggest leaving it to professionals if you can.
Toyota has an extended warranty for power door issues on some models, but it looks like you’re outside the official coverage period. However, the dealer may still be able to help you out.
Check out the NHTSA info: https://static.nhtsa.gov/odi/tsbs/2019/MC-10162786-9999.pdf
This Toyota link is easier to read: https://www.toyoheadquarters.com/threads/2011-2016-toyota-sienna-power-sliding-door-warranty-coverage-for-the-sliding-door-rear-zh5.984/
Here’s a video showing how to fix it for your model. I almost did it on my 2017 Sienna, but I ended up going to the dealership for a fix under the recall.
Watch it here: https://www.youtube.com/watch?v=TcxB9fa3WrE
Or you can check with your local dealership to see if they’ll fix it under recall T-SB-0141-18. More info is available on the National Highway Transportation Safety Administration site:
https://static.nhtsa.gov/odi/tsbs/2018/MC-10152554-9999.pdf