I have an older car, I'm not finding a speed sensor signal, but When looking up other wire codes like for the Cruise Control, there is a VSS wire, I believe that VSS = Vehicle Speed Sensor which would satisfy this connection.

Its a 93 Camry V6 Wagon, I dont really want to have to buy a ND-PG1 if I dont need too.

Thanks in advance.

Vss is what you want. =D

Is it really necessary to hookup the vss wire for the avic?

the navigation just was not as accurate without the vss wire attached. it still worked but just not as good !

Here's the location of your VSS wire. Be sure to test it to insure you have the right wire.

VSS Wire Purple/Yellow Right Side Dash at ECM 22 Pin Connector

It's my understanding it's under the right side kick panel.