the doors started locking themselves whether or not the key is in ignition turned off or key is in my pocket. i have never had a fob with car. did it pretty regularly until i took it to dealer where it failed to do so. a few weeks later it now does it almost always.. bad situation as you can leave in ignition while getting gas and getting locked out with no access. Thanks for any help
I don't know how to fix this properly, but you can disable power door locks.
According to the fuse box diagram, fuse 16 controls "Multiplex communication system (power door lock system, auto−door locking system, wireless remote control system)". So if you don't have a wireless remote control system (I believe this is the key fob, which you don't have) and can live without auto and power door locking then you can simply remove the fuse.
Two possibilities - you could have a intermittent short in one of the door lock switches, most likely the driver's side. You could try and check that switch.
Second possibility is that there are several different electronic lock/security systems sold by Toyota. One of them does automatic locking. Start engine and it locks all doors. Turn off, open door, close door, walk away and it locks. This feature was controlled by the ECU - there was some sort of sequence where you had to put the key into the ignition and turn it off and to accessory in a certain pattern. I remember this as I wanted it, but it wasn't installed on my particular car. You'd have to do an online search for that year to see which systems might have come with the car and try to get the manuals and try them.