I recently installed my avic d2 and everything is working fine (speed pulse beeps, reverse input, bypass). The only thing is that the sensor still states that it is initializing. I have been driving my car for a few months now thinking that it had to "learn". The system shows the accumulated speed pulses but no mph on the diagnostics screen and no g force related info.

Now, I have yet to install my GPS antenna (have to get a new one) but before I purchase one, do you think that my sensor will finally initialize and I will be able to view the vehicle diagnostics AFTER I install the GPS antenna?

Any insight or information is greatly appreciated.

Yes, it will do. All these wires and cables are needed for the Avic d3 to work properly, specially the VSS wire, reverse wire and the GPS antenna.