This morning my passenger door would not lock/unlock on my 2005 tsx. I tried with the remote and also tried from within. All the other doors lock and unlock except for this one. Even when using the switch on passenger side, I can get all of the others to lock/unlock. The tab moves a bit on the passenger side, but not enough to lock. However, I can lock/unlock manually. Does anyone have this problem or know what it could be?

 

It's the power door lock actuator and it's too common I'm afraid (the door effected can vary though). Many here have replaced it themselves, though it involves removing the door panel. I'm pretty handy, but this is strictly a dealer item for me (especially this time of year)(as I sit here looking at a gazillion inches of snow and it's still coming down.....).

 

Yep, door lock actuator is bad. I replaced mine myself in about an hour. The part is pretty cheap. You can find it on ebay from an Acura dealer for about $20. It's about $30 shipped.
Here's a link.
http://cgi.ebay.com/ebaymotors/2004-...Q5fAccessories

If you have warranty, let the dealer do it. Otherwise, if you're handy with the car, save yourself a couple bucks in labor costs.