karmajack

Agreed. I'd like to know as well. 

I noticed a seller on eBay offering the service of upgrading the software for AA on this series, but insists you contact before purchase. I'd like to know if the process is out of my league or not. Need more details on this for my 6100. 

How?

I chased some similar noise for a while. Turns out most of it was remedied by better quality RCA's. Stinger 6000 series did trick.  If that's not it, you can try a few other things.

Have you tried a different ground for the radio? Many times the harness ground isn't great.

Could be an inherit electrical problem with the vehicle. A big 3, or improved factory grounds might help.

A ground loop isolator like the PAC SNI-1 Noise Isolator might help. 

Gains on amps might be slightly too high.  You always have to reset your gains when swapping in a new source unit. 

I have a 6100NEX and a DD1. At 40Hz -0dB  It would distort at 37. However, with 1kHz it will distort at 33. 

For what it's worth, I don't have the speed wire hooked up and I have pretty accurate speed displayed relying on the nav/ gps. I've contemplated hooking it up for the sake of it, but found it not necessary.  This is on a 6100nex, and it's been in two different vehicles so far without speed wire.

Perhaps you need a factory reset? Pioneer recommends a reset after a fresh install.  Not sure if you did that already or not, but it may or may not help. Being disconnected from that battery only resets so much, so a manual reset might be needed. Sure it may be a pain having to reconfigure everything afterwards, but it may solve the problem. Maybe the HU is conflicted with old and new data...I dunno.   Just be sure to take notes on all your custom settings and stuff before you do so.  All your sound processor settings, eq, saved radio stations, etc.

Other than that... As much of a pain it might be, disconnecting that wire may actually remedy the issue. If it gets to a point that you can't narrow the issue down any further through other explanations, disconnecting and testing would at least confirm whether that was it or not.  Hopefully in that wire leading to the speed sensor location somewhere, you can make a clean cut and add connectors to make it easier to reconnect if need be.

Good luck and I hope you figure it out. Would be nice to hear back from you either after you solve it or reports on failed attempts.  

 I'm dying to have this for my 6100. 

Ive read elsewhere that some people have had issues with USB 3.0 flash drives, and having better success with 2.0. 

Is your drive perhaps 3.0?

I'm getting a 6100 installed very soon and I'd like to give this a try myself.  Anyone happen to know where you plug this in on a 6100?  I'm hoping somewhere on the front. Looking at images of it, I can't tell if there's a place for it. If it's on the back, would it be okay to just leave it plugged in at all times if I have the installers just plug it in and leave it?  I won't bother with it if I have to take the head unit out to plug it in and use it.  Thanks in adv.