Anyone ever see this fault code? It sounds serious! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Steve Cole · 12-12-2020, 10:56 AM

Thank you for that great explanation David, I get it now! About the alternator control module, is this something I should have taken from the donor truck?

I checked Auto Zone but they don't list one. I know where my donor truck is so I could go get it if I knew what it looked like. I figure this would be easier than trying to find someone to re-program my ECM.

ls1nova71 · 12-12-2020, 11:16 PM

The GBCM is located on the negative battery cable, 6" or so from the battery terminal. There are several wires that go to it which can be easily hooked up, but there is one serial data wire that ties into the instrument cluster. I have never tried it, but have heard it will work without the instrument cluster wired in it.

Steve Cole · 12-15-2020, 02:07 AM

Quote:

Originally Posted by ls1nova71

The GBCM is located on the negative battery cable, 6" or so from the battery terminal. There are several wires that go to it which can be easily hooked up, but there is one serial data wire that ties into the instrument cluster. I have never tried it, but have heard it will work without the instrument cluster wired in it.

Hi Eric,

You say that there are several wires that go to the GBCM, but where do they come from? It seems like GM over complicated things on a perfectly good system. That being said, I still need to get this fixed so I am looking for advice (from anyone) on the best way to handle this. Correct me if I'm wrong, but it seems like there are only two options here- re-program the ECM to charge a 2004 or earlier alternator or wire in a GBCM? Am I missing another option here?

TIA for anyone's help with this.

ls1nova71 · 12-15-2020, 11:46 AM

There are 2 powers, 2 grounds and a few that go to the PCM. The only one you won't be able to hook up is the gray wire going to the dash. Just hook the orange and green wires together leaving out the gray and it should work. I had to upload the schematic in two pics, that's why it looks funny.

Steve Cole · 12-16-2020, 07:19 PM

Thanks for the wiring diagram Eric. This option may be a little over my head so I need to get some more details on reprogramming the PCM and replacing the alternator with a 2004 or earlier one like Clinebarger does.

I will have to decide based on what I learn, which route will be the best one for me with regards to my abilities and if I can find someone in my area that can reprogram my PCM.

Steve Cole · 12-21-2020, 01:29 PM

Will this take care of my PO 622 Trouble code??

http://www.rpmextreme.com/Product/26...st-Module.aspx

Thanks,

Steve Cole · 12-21-2020, 04:44 PM

Never mind, wrong PCM. Dang.

12-12-2020, 10:56 AM	#1
Steve Cole Registered User Join Date: May 2012 Location: Faith,NC Posts: 1,623	Re: Anyone ever see this fault code? It sounds serious! Thank you for that great explanation David, I get it now! About the alternator control module, is this something I should have taken from the donor truck? I checked Auto Zone but they don't list one. I know where my donor truck is so I could go get it if I knew what it looked like. I figure this would be easier than trying to find someone to re-program my ECM.

12-12-2020, 11:16 PM	#2
ls1nova71 Registered User Join Date: Dec 2009 Location: Independence Mo Posts: 4,118	Re: Anyone ever see this fault code? It sounds serious! The GBCM is located on the negative battery cable, 6" or so from the battery terminal. There are several wires that go to it which can be easily hooked up, but there is one serial data wire that ties into the instrument cluster. I have never tried it, but have heard it will work without the instrument cluster wired in it. __________________ My '72 short bed build. http://www.ls1tech.com/forums/conver...6-0-4l80e.html 5.3 swap into my RUSTY '71 C10 http://ls1tech.com/forums/conversion...71-c-10-a.html

12-15-2020, 11:46 AM	#4
ls1nova71 Registered User Join Date: Dec 2009 Location: Independence Mo Posts: 4,118	Re: Anyone ever see this fault code? It sounds serious! There are 2 powers, 2 grounds and a few that go to the PCM. The only one you won't be able to hook up is the gray wire going to the dash. Just hook the orange and green wires together leaving out the gray and it should work. I had to upload the schematic in two pics, that's why it looks funny. Attached Images __________________ My '72 short bed build. http://www.ls1tech.com/forums/conver...6-0-4l80e.html 5.3 swap into my RUSTY '71 C10 http://ls1tech.com/forums/conversion...71-c-10-a.html

12-16-2020, 07:19 PM	#5
Steve Cole Registered User Join Date: May 2012 Location: Faith,NC Posts: 1,623	Re: Anyone ever see this fault code? It sounds serious! Thanks for the wiring diagram Eric. This option may be a little over my head so I need to get some more details on reprogramming the PCM and replacing the alternator with a 2004 or earlier one like Clinebarger does. I will have to decide based on what I learn, which route will be the best one for me with regards to my abilities and if I can find someone in my area that can reprogram my PCM.

12-21-2020, 01:29 PM	#6
Steve Cole Registered User Join Date: May 2012 Location: Faith,NC Posts: 1,623	Re: Anyone ever see this fault code? It sounds serious! Will this take care of my PO 622 Trouble code?? http://www.rpmextreme.com/Product/26...st-Module.aspx Thanks,

12-21-2020, 04:44 PM	#7
Steve Cole Registered User Join Date: May 2012 Location: Faith,NC Posts: 1,623	Re: Anyone ever see this fault code? It sounds serious! Never mind, wrong PCM. Dang.

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