Just had the same problem with my 2004 Sienna LE on the passenger sliding door. We purchased this van as a "toyota certfied model" eleven months ago, and we have only put 6,000 miles to date. My wife was left stranded with three kids (ages 1, 1, and 2 - all in car seats) because the door would close - didnt want to subject the kids to driving with the door open on a 20 degree night! I had to go out and pick up the kids (in another car) and drive the car home myself with the door open (thank God for cell phones).
Took the van to the closest Toyota dealer I could find (was not the dealer I purchased the car from) and was told the total cost to repair is over $1500 (5 hours labor at $95 p/h plus $1,000 parts for a new motor and cable assembly). You want to know a funny thing...? I just found a Toyota OEM sliding door motor on
ebay for $149.
Of course, this was not covered under warranty. Made the dealer disconnect the motor and convert the door to manual (still charged me 5 hours in labor) so I can drive it back home.
Now gonna take this up with the Toyota Dealer that I bought the car from originally and make them get it right for me.
I am sure this is a widespread problem and should be viewed by Toyota as a a SAFETY ISSUE.