I just spoke with pioneer tech support and they said I do not need to install the vss wire b/c the unit has a gyro sensor that can take care of calcuations and such. I have a 2003 Mercedes Benz E55 Amg which does not have a vss wire and runs through a canbus system. If you take into the sensor wires off the wheels then the abs and traction control don't work and mess up too. Pioneer told me also not to tape into those wires. just wanted to hear your thoughts guys and if this is indeed true. I know the unit will work without hooking it up and so will the GPS but he tells me that I will not loose any quality. I asked him what if I went underneath a tunnel, he said the gyro sensor would help to continue to work so you eta, etc. would still be accurate BUT you would loose satellite signal (obviously )

Yup, it's not needed. But it's nice to have.

Mine hasn't been connected ofr the last 3 months. The only difference I noticed between connected and not is when I get in and start driving the unit was a little more accurate with vss hooked up. But the inaccuracy corrects when the avic gets a gps lock.

ok great thanks guys =)

It works WAY better with the VSS wire hooked up. I'm having VSS issues right now where it will be able to read the speed pulse sometimes and will have difficulties others and I can notice on the navigation tracking when it is and when it's not working. When there's clouds in the sky or if you're in between tall buildings it will have trouble pinpointing your location if not for the VSS.

From what I understand if you do not connect the VSS, you will lose 3D capability. In addition, some of the diagnostic data cannot calculate such as slope.

From what I understand if you do not connect the VSS, you will lose 3D capability. In addition, some of the diagnostic data cannot calculate such as slope.

I wondered why "slope" didn't work for me...