Can Any one give me a site or some info on pin location for a 2002 ECM?? I would like to know what the unused pins on my ECM are for.
Thanks. :)

I'd love to see this as well.

I'd love to see this as well.

Wouldn't we all:) , I don't think it there is any publication besides the actual circuit board schematic (board in the ECM) and who would have that besides GM and....who makes the ECM's...delphia? I have in front of me the snap on and shop key diagrams and they still don't post what the unused pins are for. I only see getting every wiring diagram there is for all the vehicles this ECM is used for and then just deducting from one to the next....and who is gonna do that? LOL

I do know from the 2000 5.3 1500 silverado to the 2002 6.0 2500HD I found the o2 heaters to have different pins (especially depending on whether or not they are case or isolated ground). Those pins were labeled on the '02 ecm but not on the '00 ecm.

Any help? I have 4 more pages of diagrams. Not sure if you'll be able to see in this post but, if not PM me and I can e-mail it to you. :drive: Edited for a better picture...How do I make it huge so you can read it?

http://i7.photobucket.com/albums/y260/Baumgardner2051/ECMWiring_2.bmp

So did the one I e-mailed give you the info you needed? I have others for the same PCM/Truck. If you need the others let me know and I can scan them in. If anybody else needs them PM me your e-mail address.

What specific thing are you trying to look for? I know what all the un labeled outputs are, But they also need turned on in the hex. If you tell me what specifically you are wanting to do, ill help you out. Jes

since Jes chimed in, I will do a minor hijack. :offtopic: Why does my truck drop to 350 or so rpm when the A/C compressor kicks on if I'm at idle. I swear it almost stalls the truck. I had 2 or 3 dropped injectors for a month and finally got the wiring fixed. The ac problem seems to be getting better over time (last 2 days) is my pcm just relearning how to run with all 8 injectors firing instead of 7 or 6 or 5 depending on the day?

I know that pin 42, once the pcm is activated, is for the electric fans option.

I know that pin 42, once the pcm is activated, is for the electric fans option.


Thats pretty much what I want to know. (for now) With HPTuner there is options for the fans to turn on low and high speed. With a nelson harness (only using pin 42) the ECM only controls the fans low speed. I want to know what pin I could use for high speed. But the more I think about it the more I doubt it is possable, because if it was Allen would have done it that way too.

The other output for highspeed fan when turned on is pin number 33 on the RED connector.

They are a negitive output from the pcm. so to wire a relay you would do.

30 all time battery
85 all time battery
86 output from computer fan turn on
87 lead to positive side of fan,
87a is left blank.

:)

And to make a performance button and auto/manual transmission shifting button i can do those also.

So the ECM controls the ground on both fan setting right?

yes that is correct.

Does this mean you have a harness for fan activation to make it work like the stock version instead of what Nelson does?

TTT do to PIN 33 is already used up on my truck.... I really need to find out the other pin location for the fans.........

could the unused pins be used for inputs for wideband afr, fuel press., egt, dual tune, valet mode, nitrous, et cetera? What about outputs for certain gauges?

It is my understanding that the Pin 33 only works on 03+ PCMs.

Thread link read from page 7-10
http://www.performancetrucks.net/forums/showthread.php?t=376992&page=7&pp=10&highlight=blowing+relay

GM Factory Efan wiring harness, dual speed.
15216055

i hope that helps

could the unused pins be used for inputs for wideband afr, fuel press., egt, dual tune, valet mode, nitrous, et cetera? What about outputs for certain gauges?

That may be an option..

Blown02Sierra, you are 100% correct..

This thread is abit older, I bought a aftermarket fan controler and temp sensor to control the other setting...

Sorry i did not even notice the dates...

could the unused pins be used for inputs for wideband afr, fuel press., egt, dual tune, valet mode, nitrous, et cetera? What about outputs for certain gauges?
People are already using the wires for the egr they are removing for a wideband feed, which can be read through HP Tuners without the enhanced interface.

Well, i never had egr and i'm using efilive. Is that still an option for me? And what about the open pins? Also, can my 02 pcm use pin 33 for the hot setting>?

nope, not with the 02 ECM. 03-05 you can use 33 to control the fans.
And yes with the EGR, you just need a pin location. But I'm not sure with EFI...