After putting about 2000 miles on my new 2007, the tire light came on. I did everything you did, then took it back to the dealer. He checked it out and asked if these were the original rims and tires I had purchased it with. They were. He then informed me that all the tires needed to be taken off the rims, as they were no comunicating with the computer sensor. I left it for a day and when I picked it up, you could tell that each tire ( finger prints all over the rims ) had been worked on.

He said they had to " reprogram " everything.

No problems since then. Wonder what they really did ???

Maybe this will help.

Service bulletin for 2008 4Runners regarding Tire Pressure Warning Valve/Sensor Activation

T-PD064-07 Service Bulletin

I really hope that they weren't dumb enough to dismount the tires (all 5 of them - the spare is part of the system, too). If they plug their scan tool into the OBD port, it can see exactly what's going on with the system. It's true that the sensors have individual ID numbers that are programmed into the computer, but the factory would have taken care of that if they're the original wheels. The only reason to dismount the tires is if the programming is wrong and they need to read the ID numbers on the sensors, and the only way that would happen is if someone swapped wheels.

Always make sure the pressure in all five tires is above 27 PSI, the set point for the sensors. Also, compensate for outside temperature changes. You can't be at 30 PSI in a nice warm garage when it's 20 degrees F outside - the cold will make the pressure drop about 1 PSI per 10 degrees F of change, and the light may come on after being outside for a while.