Fpcm 2012-2014 zl1 can

[christian moller]

Hello
i'm wiring up my Datsun 260/LSA swap and noticed that on the FPCM there is two CAN high and two CAN low.
Is this one high/low going to the modul and the other going to another module from this one, does it matter which two of them i use?
And the black "drain" wire, what to do with it

Thanks and have a nice day
Christian

"FSCM D,2012-2014 GM
Serial:GA2265DC40340885
OS:22872238 "

K27 FPCM_2.jpg

[gtstorey]

Do you not have full wiring diagrams for the donor? Pin outs really aren’t enough.

But the only difference it should make as far as in or out is to make sure a module with a 120 ohm resistor is at each end of the chain.

[christian moller]

no, sorry i dont have the complete diagrams, i have a diagram from a cadillac and it have worked good so far, the thing that differs is the FPCM...........
The FPCM is at the end of the CAN, should i put a resistor at the two extra High/low?

Thanks
Christian

Edit: I created an account at ACDelco TDS and tried to download ,no luck, it could be crap behind the keyboard though

[gtstorey]

Alldata.com will have diagrams also.
All I have diagrams for is 2010 Camaro and it has the resistor showing between pins 5-17 of the FPCM.

[christian moller]

Thanks, i'll check Alldata.com
Looks like a resistor is in place then

Thanks again
Christian

[blindsquirrel]

It can also go 'inline' with any of the other modules, all the CAN+ pins are the same as any other, all the CAN- pins are the same. Wiring it up as DLC -> TCM -> FPCM -> ECM (which has in internal resistor, and only one pair of CAN pins) would be the cleanest diagram-wise. The exception would be if the FPCM is located way off somewhere all by itself and putting the terminating resistor there would avoid having to run another pair of wires back to where the other modules are.

[christian moller]

Thanks for the info on this.

/C

[gtstorey]

It can also go 'inline' with any of the other modules, all the CAN+ pins are the same as any other, all the CAN- pins are the same. Wiring it up as DLC -> TCM -> FPCM -> ECM (which has in internal resistor, and only one pair of CAN pins) would be the cleanest diagram-wise. The exception would be if the FPCM is located way off somewhere all by itself and putting the terminating resistor there would avoid having to run another pair of wires back to where the other modules are.

Does the ECM always have a resistor? The one I looked at for my Camaro doesn't show one for the ECM. But it actually only showed one on the High-Speed Circuit and one on a secondary high-speed bus that was the EBCM related modules. I may have not dug enough since all I looked at were the comm bus diagrams. Or maybe they stopped showing the internal module resistors at some point in GM diagrams.

[blindsquirrel]

If there's only one pair of high speed CAN wires to a module, then it's got an internal resistor.

(I had a whole thing already written up here but the forum decided not to fully load the whole page, like it seems to do A LOT, and F5 made it all disappear, and the 'restore saved content' thing isn't appearing so that's great. Welcome to our glorious techno-future. Enjoy your stay and if you experience any problems, out automated chatbot is here to offer nonsensical suggestions designed to frustrate you until you give up and go away.)

A T42 also has an internal resistor, it just doesn't get tied in when the TCM is hooked up as inline style. When the TCM is off on its own someplace (Express van, with ECM/TCM on opposite sides of the engine bay) the terminating resistor gets connected via jumpers.

GMLAN inline simplified.png GMLAN Y simplified.png

I am clicking Submit Reply now before anything else goes wrong.