Hi All,

I did a 4L80 swap in my 2001 C3 AWD, I am having a issue with the Torque Converter not locking up. I did the white/brown wire swap and added the two wires for the input speed sen. The trans shifts thru the gears fine but he ECM is not sending the lock up signal to the trans. I ran a switch to the brown wire and the TC locks when I ground the wire.

The truck harness is pinned out - A=light green, B= yellow w/blk strip C=red w/ blk strip D=lt blue w/ white strip E= pink L= yellow w/brn strip M= gray N=pink P= red R=drk blue s= white (white/brown swap) there is a tan w/ blk strip in T

The trans is pinned out - A= Lt blue B= purple C= yellow D= red E= red L=black M= drk blue N= orange P= pink R= gray S= brown

I don't know if there is a difference in internal harness pin out color and can't find a pin out that matches what I have.

Any one have any idea's.

Thanks

Steve

 

So, you pulled the white and brown at the PCM and put the white into the brown's position(pin 2 of the green/red PCM connector)? And left the brown disconnected? Looks like you left the harness connector alone.

https://www.performancetrucks.net/fo...d.php?t=413157

 

I did the white / brown wire switch at the connector on the truck harness and ran the two ISS wires to the ECM.

 

OK. Then the brown should be at pin S of the truck connector and teh white disconnected. From your firspost it sounded like you might still have the white at pin S.

Trans side pinout below:

 

I did the white / brown swap (I just verified the brown wire is in the S position) the trans wiring is correct (thanks for the diagram) I was rhinking, is it possible to have the park safety switch 180 out, when I reinstalled it I checked that the reverse light came on with the gear selector in reverse. Im starting to think that the ECM is the issue.

Steve