Ok, so I got the unit installed and it works fine, but I was unable to locate the appropriate wires from the ECU to allow it to work in AUTO mode (I don't have a service manual). I need to tap into the ECU ground and rear O2 sensor wires and would like advice from anyone who's hooked up a similar unit. Links to "how-to's" would be fine too.

Anyone?

Can I use the FRONT O2 sensor for a more accurate reading?

Bumpity, bump.

Here's a link to the '02 WRX ECU map. I chose the rear sensor because I hear it was more accurate. Just match up the look with plug and splice in! (The one you want is B17).

http://66.92.133.228/tr/wrx/my02usecupinout.htm

Good luck!

Ian

You can't use the front sensor because it is a wideband unit and doesn't produce the type of readings your TT is looking for.

Thanks for the replies folks.

I've already seen that pinout chart since I last posted, so I know which one is the rear O2 now. But which ground near the bottom of the list is the ECU ground? There are five listed: (sensors), (injectors), (power supply), (control systems). My best guess is (power supply), but maybe (sensors).

I'm probably being anal about this, and I know the A/F meter is just a pretty lightshow :rolleyes: but I'd still like to do it right the first time. The instructions specifically say to tap into the ECU ground (maybe for the accuracy of the reading?) so that's what I'd like to do. I know in theory, a ground is a ground, but I'm big on following instructions:alien: .

When I put my APEXi TT in last year I just ground the black wire to the car itself. Maybe this is wrong, but I've been getting good readings ever since. Nothing has gone "haywire" or anything. As for your ECU question....search me.