My 2103 situation is the car is driving around just fine then BEEP there's the triangle and gas pedal does practically nothing and if you come to stop you're not going to move after that. This morning I was able to remove the glove compartment and disconnect the ECU connector that has the wires leading to the TAC and plug it back in and the car turned on and I continued the rest of my drive no problem. Some history: I had this problem about 16 months ago and I couldn't seem to resolve it so I bought a "new" TB and installed it. Here we are again. The new TB was only $114 did I get a fake?? It does say "TOYOTA" on it. It's not that dirty. The return spring is super clean still. The throttle plate has a little gunkus on it but the shaft rotates smoothly in both directions (however keep in mind the motor is being turned as well). I'm going to disassemble the TB I took off the car last year and compare. I did do like the repair manual said and ohmed the wires to ground and it reads infinite like you would expect. The motor terminals measure 0.4 ohms on the "new" TB I still have find the old TB and see what that motor measures.
Do you have any symptoms like an unsteady idle? I bought a used TB's at wrecker for like $45 before... Buying brand new for an old car doesn't make any sense.
A diagnostic trouble code starts with an alphabet letter followed by four more digits. The 2103 is not a complete trouble code. I assume that you mean P2103 for the trouble code.