pioneer deh p6000 wiring pinout

It is probably going to take me longer to type this than it will take you to identify them.  First find the ground wire, it will be common with the chassis of the radio.  Then set the meter to diode test, black lead on the gound wire, red lead to the wires one at a time, just notice the readings, now reverse the leads and recheck each wire.  There will be one wire that reads between point 400 and point 600 with the leads one way and when the leads are reversed it will start low and climb to a much higher number.  This wire is the constant wire.  There is a diode across that wire.  That is why the reading is so different depending on the polarity of the meter.  When you were checking you should have noticed 8 wires that had the same exact reading, there may have been a difference when the leads were reversed, but all 8 should have been consistent.  These are your speaker wires.  Then there should only be a few slots left unidentified.  These wires will be the switched wire, the amp remote wire and possibly a separate power antenna wire.  You can apply 12 volts to either of these wires without damaging your unit.  Connect the ground wire to ground, apply power to the constant wire.  Now apply power to each of the 3 remaining wires, one at a time until you find the wire that is the switched wire.  Once you find it, you will need to figure out remote and power antenna.  The remote wire will have 12 volts on it anytime the unit is powered up.  The power antenna wire will have 12 volts only when the AM/FM is selected as a source.  It may not have a separate power antenna wire.  The speaker wires will be layed out with all positives on top row, or the config will be + - + - , you will have to use the scope and balance left and fade rear to see which 2 wires have signal on them.  Those 2 will be left rear speaker.  Now balance right and check again those will be right rear.  Now fade front, those 2 will be right front.  Once you figure out the layout of the speaker wires it will be easy to identify positive or negative. 

If you are uneasy applying power to the wires to find the switched wire, identify the other wires and using MS paint, draw a picture of the plug with the slots you have identified, I can probably tell you where switched is located.  Or place a 1 amp fuse in line with the wire that you are using to find it.