I own a 2000 IS200 and my problem is that the lock sometimes obey and sometimes do not obey the key-less entry. I changed the battery of my remote but the problem continues. I also used the key to open the doors by inserting it in the drivers side but some locks obey and other do not. The same problem occurs when I am inside the car and try to lock it from my door, some work and some locks do not.

 

a DIY i put together a few years ago - there are other similar DIYs as well on the forums
http://my.is/forums/f221/diy-guide-d...-motor-414788/

the pics are not working - i can try to get them to by email if you want (i would need to look for the originals) - just PM me about the pics if you want them

but it is possible its the door actuators - your symptoms sound like the problem i was having (albeit i twas only my driver front door that was giving me issues).

 

Thanks, Soon as I get it I will send it to you.