If you look at sheet 1, D1 is system gnd-blk/wht and D2 is sensor gnd-blk/red or ppl/blk depending on model/yr. So it's your choice.
If you look at the wiring FAQ you will see a pic of the actual circuit board in the ECM.
I have the solder joints from the connectors labeled. Look close and you will see D1 and D2 are actually tied together inside the ECM. So electrically they are the same location.
