I have a 06 TR and I'm trying to install the Apexi TT and stuck on where to tap both the black and white wires. I looked at the wiring manual, and the diagrams doesn't look like anything of the actual harness.

I have the factory manual, and there are several O2 signal wires and grounds. Someone pls help. . The harness configuration is exacly like the 05 STi with very few difference in wiring. Thanks!

 

Update: I called Apexi and basically found out nothing. They told me that they do not know what wires to tap for the 04,05, or the 06 WRX/Sti. They also told me that it might not even work with these models. I didn't want to bother arguing, so I hung up. Now, this is all BS and they don't know their product too well. Now I am completely stuck... Im sure someone installed this into a MY05 STi, I just want to how they figured it out. Thanks

 

I called them again, and I got some useful info this time. The guy said "look for the O2 wire that has 0-1.0V and the corresponding ground". So I look for that on the wire diagram, and found:

Front oxygen (A/F) sensor heater Signal 1 0-1.0V
Front oxygen (A/F) sensor heater Signal 2 0-1.0V
GND Front oxygen (A/F) sensor heater 1
GND Front oxygen (A/F) sensor heater 2

I think I narrowed it down to four wires. Question now is: does it matter which one I tap? (1 vs 2)

 

Save yourself a lot of time and don't even hook up to the Air Fuel signal. The stock one is not good to tune off of. Knowing the stock A/F mixture is worthless in my opinion. The turbo timer is also a waste of money if you are still running the stock turbo.

 

I guess it's only gonna be good for a fancy battery voltage meter... >_< sigh.
Wasn't gonna use the timer function anyway, thought it would've been a nice interior gadget. oh well.