In order for the ECU to go into diagnostics mode, a few prerequisets must be met.
A) Battery Voltage must be above 11volts
B) TPS must be in IDL
C) Neutral Start Switch must be connected (or Auto Trans in Neutral)
D) Aircon/fan switch off.
To check the TPS, look here.
http://www.cygnusx1.net/supra/library/TSRM/fi/FI_101.gif
Ignoring the thickness gauge settings, just make sure the IDL-E2 setting are correct.
(ie, open circuit when throttle is shut, and short circuit when throttle is 0.5mm open).
You may have to clean the throttle body in order to get the butterfly to close all the way.
If the butterfly looks like it is closed all the way, you can adjust the TPS with the 2 screws on the side.
Pin out is the same as the 7M-GTE one.