Before you go to the dealer, check the output voltage of the TPS. Backprobe the white wire of the TPS connector with key off. DO NOT PIERCE THE WIRE.
With key on engine off, the voltages should be as follows:
Throttle angle// Voltage
0 deg// .65V
10 deg// .97V
20 deg// 1.44V
30 deg// 1.9V
40 deg// 2.37V
50 deg// 2.84V
60 deg// 3.31V
70 deg// 3.78V
80 deg// 3.9V
If you don't measure anything, make sure you have battery voltage on the yellow wire and ground on the brown. If this checks out good, you'll want to check the voltage drops on all three wires.