SLIDING DOOR CABLE SNAPPED

Try an obvious thing first. Check the actual runner channels on the body of the vehicle aren't full of dirt and rubbish. I've been caught out by silly stuff like that!
This sounds like it might be an issue with the 'Automatic' part of the door. Does the Auto close still work? Something might have come loose inside the mechanism and is blocking the doors movement.
If the door was off it's tracks the door wouldn't sit right when closed and you would have trouble locking it. The door would look either twisted, where the door gap is wider at one end than the other, or it would sit further out at the top or bottom as you look down the side of the vehicle, where it's jumped out of its runners.

You probably have a bad cable. Call Toyota, they had a "customer satisfaction" recall for this problem.

Most likely the motor assembly has died or has become disconnected.

Can be issue with the switch.
Help links are provided below for detailed procedure,Click the link below:---
Front Door dis-assembly diagram for Toyota car?

http://repairhelpcenter.blogspot.in/2012/02/front-door-dis-assembly-diagram-for.html

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Rear Door dis-assembly diagram for Toyota car?

http://repairhelpcenter.blogspot.in/2012/02/rear-door-dis-assembly-diagram-for.html

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How to test Power door locks? http://repairhelpcenter.blogspot.in/2012/02/how-to-test-power-door-locks.html

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right side slide door light switch on Toyota Sienna? http://repairhelpcenter.blogspot.com/2012/01/details-for-replacing-right-side-slide.html

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Door locks not working? http://technoanswers.blogspot.com/2012/01/door-locks-not-working-on-ford-explorer.html

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Power door locks not working? http://schematicsdiagram.blogspot.com/2011/12/power-door-locks-not-working.html

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Repairing car Door lock Actuator?
http://howtobyme.blogspot.com/2011/11/repairing-car-door-lock-actuator.html

How to Access car door panel?
http://howtobyme.blogspot.com/2011/11/how-to-access-car-door-panel.html

Vehicle door panel components?
http://howtobyme.blogspot.com/2011/11/vehicle-door-panel-components.html

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This will help.
Thanks.

well they dont use cables they use a iron rod so just snap off the pannel the snaps are in the out side of the door then just remove the arm rest and the panel comes right off remove the dirt cover then just tighen it and it will work again

Here is a fix for a 1999 Sienna with a broken door cable.

If you can remove the inner door panel you will see a maze of cables running to the various locking points on the sliding door. If the cable going to the FRONT latch on the sliding door is broken (or in my case, simply dislodged inside the door) the door acts as if it is frozen shut.

The front cable is short, and easily replaced even by a newbie mechanic.

DO NOT PUSH IT!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1. turn off the power button for the power sliding doors located on the lower dash area.
(in for on out for off)
2. close the sliding doors
3. disconect the battery and wait 1 minute.
4. reconect the battery, turn on the power switch
5. use one of the door control buttons open and close the door this should reset the door.

If this fails to get it working i'm sorry but you will need to take it to a dealer.
and most likly it will need a new drive $3000 aproxmatly. it can not be serviced

I have exactly this problem on my 2004 toyota sienna. Just started happening and the door now rubs the edge of the rear quarter panel as the door opens and closes. Any help on how to replace the middle hinge would be appreciated.

You need a motor assembly for the power door. It comes with the gears and cables all as one assembly. It requires taking apart the sliding door from the inside. Removing the door panel, door glass, window regulator and motor assembly to gain access to the unit. This is not a job for a novice, and can be a costly repair. Check around for the best price from a place that has experience in Toyota sliding doors.
You cannot just replace a broken cable.