Quick, random question fellas.

So, my WSP CA to S13 harness has two red plugs that originate directly next to the CTS 2 pin sensor. I have had one of them installed, on a guess, since I have finished my swap. Ive had 0 issues idling, driveability, etc. Runs great.

Install my Nistune ECU and it throws the CTS code. I switched plugs to the other red connecter, and it only barely starts after 10 min of turning it over and the idle is pretty rough. Though, the CTS code doesnt come back once I clear the DTC codes. Switch them back to the "wrong position", and the issues go away but the code comes back. And of course, with Nistune, with the CTS or AFM code thrown, it goes into a limp mode and cant be consulted.

I have a tuning appointment coming up in a couple of weeks, and want this figured out before I go. Any suggestions?

IIRC (I haven't had a stock harness in a LONG time), one red plug is for the CTS, and the other is for that cold start/fast idle valve under the TB.

Ryan is right. I had the same issue. Grab a multi-meter and the FSM and test the two plugs for what kind of voltage they are supposed to be getting.

except for one red connector is for the CTS and the other is for the AAC valve I believe.

Maybe that was it. I do remember there were 2 red plugs that could plug into two different places.