I was looking at the valet key vs master key, and the laser cut part looks identical.

If the valet key can't open the trunk, glove box, or passthrough......
Does that mean there's a different transponder in the valet key?

Are there transponder receivers in the trunk, glove box, and passthru?

 

Programming logic, not duplicate receivers. That key has its own identify, just like other keys that set your driving position etc differently for key 1 and key 2

 

I will qualify that above answer with it depends on the model/year.

My 1992 SC300, well the valet key definitely looks different than the main key both in the shape of the head and the metal "key" part itself.

The main key, well that would be cool if it had my seat/steering wheel position memorized, but I doubt it does. I think its just a metal key with a remote transponder to lock/unlock the doors. It has a very small button on the side of they key that does the door locks, if you want in the trunk, well, you need to put the key in there and turn, or hit the button by your left knee in the dashboard.

 

On my 2GS, the Valet key is identical except the remote buttons on the master. From a physical inspection the Laser cut part is identical. I spent some time looking at both keys when I bought my 2nd GS, my GS430. The Valet key is identical but a little shorter because i sat there and insert both keys in the Glove box and Trunk to see why the identical valet key won't turn like the master. The Valet key on my 2GS is shorter than the master key..

 

I had a 92 LS and my parents had a 91. They had their master key, and it was thicker and had a built in fob(only for the lock/unlock button).

My car's master key was long missing by the time I acquired the car. It had only a valet key(and half of the plastic bit was broken off). I ended up having copies made of that key rather than shell out $$$ for a new master.

I never realized the key wouldn't open the trunk until I had a dead battery one day and needed to get my jumper cables out. There was some swearing that day.

 

There are only transponders by the locks when you have a proximity key system. With older style keys, the chip in the key is only read by the ignition switch. There's no chip in the trunk; the valet key is just cut slightly different so it can't unlock the trunk or the glove box.