[Fluxaholic]

You might want to check out the website www.avic411.com. It's for installing and bypassing the Pioneer Avic series, but the people on there can probably tell you about your model too.

 

[Fluxaholic]

As William pointed out, the Pioneers have a gyroscopic sensor in addition to the parking brake wire. So just grounding the parking brake wire is insufficient. You have to "fool" the gyroscopic sensor as well. A number of the units have various workarounds, depending on the model and when it was made.