[spleck]

By the way, we had a similar problem. Took two dealers to find that TSB that describes how to initialize the TPWS. This was back in 04 a couple months after we got the RAV4.

Here's what it says:
1) Adjust all tires to the standard air pressure.
2) Turn ignition to ON with vehicle stopped. Check that the low tire pressure warning light blinks twice a second.
3) Push and hold the tire pressure warning reset switch for 3 seconds until the light blinks 3 times in 6 seconds (once every two seconds). After that, make sure the light goes off.
NOTE: If the light does not blink, release the switch once and press the switch again.

After you drive under normal conditions for 30-60 minutes, initialization will be complete and sytem will begin monitoring tire pressure.

Or you can become a member here and download the full TSB.