pcmhacking.net

Hiya,
To me this is very important in tuning a swap car. There are many strategies that help with idle control. The ECM/PCM needs to know these so it can learn and repeat. It learns idle/park, idle/gear, idle AC/park, idle AC/gear, etc etc. This is for the P01/P59 but should work for many. You only need to use C1 for the computer to know gear selection(WRONG! and edited below). If you want neutral safety and backup lights, you will also need to use the C2 connector.
Enjoy

Hiya Folks,
Edit, I worked on same swap car yesterday, You DO need the 12v Ign supply and ground on C2. Shoot typical crap, a bud hooked up ONLY the 4 wires to C1 and said it shows all shifter locations on his scanner. The end customer decided he wanted a milder camshaft(the original idled at 80kpa in neutral with a stock TQ convertor )

I went by yesterday to touch up the tune with the smaller cam and PRNDL didn't work. Verified all the wiring, nada. Bought a new PRNDL switch, nada. Tried EfiLive scanner, HpTuners scanner, after using my regular stuff, nada. Hooked up the 12v and ground. Worked perfect

I generally don't physically work on the vehicles often, I just tell them fix this or that. I had to get involved this time, good learning experience since I had never done it myself.

The in/out gear was incredibly better immediately and flawless after it learned.

I apologize for the bad information.