Speed Sensor/2000 Montero Sport

I've installed a pioneer nav system in my 2000 Mitsubishi Montero Sport and want to double check my wiring.  Where is the speed sensor located and what color is it?

I'm asking because I had it hooked up to what I think is the correct wire and it was working fine.  A day later my check engine light came on, the speedometer stopped working, and the navigation diagnostic screen says it's not connected.  I've checked all the fuses, and they're good.  If I unplug the wire from the speed sensor my speedometer works, but the check engine light is still on.

Thanks for the reply. 

Yep, I do have the right one. hmmmm.  My cruise control has not worked for a long time and my abs has gone out briefly a few times.  I wonder if my speed sensor is bad.  If that's the case, why would my speedometer start working when I unplug the nav unit?