I had my Avic D3 installed in my tacoma for about 4 years/50k miles with no problems. my truck started having some really weird issues though. It wouldn't go in reverse and would die all the sudden. usually after the truck was really warmed up, but very sporadic. I took the truck to AMCO and $3500 dollars later, pulled transmission, replaced all transmission sensors, and two new ECU's they said it was the VSS speed sensor that I tapped into on the ECU. I hooked into the Green/Orange wire just like everyone else. I've heard of this problem on one other occasion with a tacoma on the internet but don't really see tons of people having this same issue.
Anyway, is there anywhere else that i can hook up that VSS wire? The Nav unit does not work without it. I don't want to hook it back up to the same place. That was a terrible experience. Since they've unplugged it the truck has worked just fine.