Originally Posted by 
CRXer
				 
			black/yellow usually denotes 12V,so its prob for one of the emiision control solenoids like purge or something.
u cant find a red/yellow wire in a 2pin plug plugged up to something else?
what about near the intake arm as ecu-man says?
even check for a red/yellow wire at the ecu end,if its there it will appear at the motor end.
if u have a look at the ECT,it will be red/white + another green/??? wire,the exact colour of that green wire will be the same as the IAT,its a common ground(same green wire appears at TPS as well)