lsxponcho

This is a bit of a continuation from my last thread. Just for informational purposes, I’ve taken a 4.8/4l80 combo from a 2007 van, and put it in my 06 sierra that was a v6/5spd. After moth balling the van harness, I found a 06 silverado donor 4.8L, with harness, tac, ecm, bcm, and column, for cheap. The only down side was the round connector off the 4l60 was cut off. I cut the pig tail off the van harness, so I just have to connect it to this new donor harness, and I’m should be off to the races. Just my luck, the pinout diagrams that I’ve seen are all different wiring colors compared to this 06 truck harness. The 4l80 pig tail also has way different colors then what I’ve seen on diagrams, but at least its lettered, so that’s no biggie.
So I broke out the multi meter, and tracked down their locations in the C1 & C2 connectors at the pcm. Here’s what I found

C1(blue) – C2(green) / description / wire color / 4l80 plug terminal?
C1-pin 17 / trans fluid press “b” / dark blue / R
C1-pin 18 / trans fluid press “c” / red /P
C1-pin 53 / low reference /grey /?????
C1-pin 75 / Ign voltage /pink /E
C1-pin 79 / 3-2 shift /white /not used…move
C2-pin 2 / TCC PWM /brown /S
C2-pin 6 / line press high /red black stripe /C
C2-pin 8 / line press low / light blue white stripe /D
C2-pin 42 / tcc solenoid valve control / tan black stripe /not used…move
C2-pin 47 / 2-3 shift / yellow black stripe /B
C2-pin 48 / 1-2 shift /light green /A
C2-pin 51/ trans fluid temp /yellow black stripe /L or M?
C2-pin 63/ trans fluid press “a” / pink /N

My questions reference the above;

-Is the low reference used as the other atf fluid temp, and if so does polarity matter?

-Can I just move the two un-used wires (C1-79 & C2-42) to C2-22&23 for the secondary speed sensor on the 4l80, and terminate them to the speed sensor I cut off the van’s harness. This would save me running parallel wires to the harness.

If this all looks good, then I will go ahead and wire the connector in…just wanted to double check.

lsxponcho

I looked up low reference, to understand that its basically a ground, and so I used it as ground side of the trans fluid temp. Wiring is all done, and pins moved into C2 for the 2nd speed sensor. If anyone see's anything that otherwise doesn't look quite right , please let me know.

Mean Green z28

iTrader: (19)

If it has a Hi and Lo, I'd keep them independent of any other circuits. You never know how the PCM uses those signals to detect faults in those circuits. Something like a Pink supply voltage gets split inside to power all the solenoids and the signals to activate them are negative signals. Things like the transmission fluid pressure switch signals use the transmission as a ground side instead of having a ground wire ... in essence, if GM didn't need to run a separate wire, they wold have saved some money haha