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Codes. Truck won’t move

dbrannon79 said:
something to consider. if that donor TCM from the 01 is of no use, and it's not one that takes the prom chip like the old OBD1 systems. you might see if it can be re-flashed for your truck and even add a tune for some advanced shifting points for better towing. then keep your factory one as a fail safe spare. I'm sure some of the guys here can recommend a good person who can do that for you.
Click to expand...
Quadstar tuning ?
 
Next step is to command it on with the scanner an it should have 12v to it.

If that's good them look over the wiring and connectors for that circuit and see if you find anything. Test for a short to power and ground. That code sets if it detects an open circuit, or a short to power/ground.
 
Rockabillyrat said:
Next step is to command it on with the scanner an it should have 12v to it.

If that's good them look over the wiring and connectors for that circuit and see if you find anything. Test for a short to power and ground. That code sets if it detects an open circuit, or a short to power/ground.
Click to expand...
Going to have to do this tomorrow. Need to get the bio directional scanner back again


What’s the reasoning for the G solenoid. Does it do something for reverse and why I was getting the double engage feeling last night
 
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Anyone have any ideas

A friend said maybe the NSBU switch

I put a new one in at the start of this ordeal.
It’s a black one. No alignment to come with it. I ordered a second one and that one arrives with no tool either so I sent it back.


Looking at this wiring diagram. Is there a way I can jump the switch and bypass it.


This seems so weird to have reverse then not have reverse.


I appreciate everyone’s help . Hopefully get this sorted soon.
 

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So looking at the NSBU plug


I took circuit 4,5,6,8 out one at a time. Hooked 12 bolts to one end. And a light in the middle and ground the other end

Light brights up. With volt meter. Each line measure 12.88



Then with the red TCM connector plugged back in. I went to the NSBU. And used the volt meter on circuit 7 which is ground and circuit 12 ignition

I get 9 Volts



When I ground to the frame I get 12



Looks like that ground circuit is bad


Thoughts





I know the ground circuit comes off the right side frame rail for this aswell. We’re is the ground junction block
 
trace them down and clear them well. do you still have the original switch you pulled the first round? try connecting it off the trans and move it watching the scanner to see if it will display all the gear selections. these do have a sort of adjustment to them when mounting to the shift shaft of the trans. I have not had to replace mine so I wouldn't know exactly how to adjust it.

@Rockabillyrat I'm sure has dealt with it before.
 
dbrannon79 said:
trace them down and clear them well. do you still have the original switch you pulled the first round? try connecting it off the trans and move it watching the scanner to see if it will display all the gear selections. these do have a sort of adjustment to them when mounting to the shift shaft of the trans. I have not had to replace mine so I wouldn't know exactly how to adjust it.

@Rockabillyrat I'm sure has dealt with it before.
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I don’t have the original.

Baby rockabillyrat. Know where the grounds 1,5 from gray. TCM go to. Or what other components use those grounds


I can follow them both to the splice pack. From there I don’t know



want to check every possible place that these two circuits go Or what else uses g103 ground
 
CBR consulting said:
I don’t have the original.

Baby rockabillyrat. Know where the grounds 1,5 from gray. TCM go to. Or what other components use those grounds


I can follow them both to the splice pack. From there I don’t know



want to check every possible place that these two circuits go Or what else uses g103 ground
Click to expand...


Looking for the location of we’re pin 12 goes.
I should have constant 12 volts here with the ignition on correct ?
 

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Yes. both 11 and 12 should be hot with the key on.

for the ground, look up around the trans bell housing bolts and see if you can tell if there is an eyelet on one of the bolts. other than that, there is also a ground on the frame back by the fuel tank. then the rest of the grounds should be up under the hood in various places. ECM ground might be located on the passenger side of the intake near the trans dipstick tube location. that's where they are for our trucks.
 
when you tested pin 12, you probed pin 7 for ground? did you also move the probe from pin 7 and try it on the frame or trans housing to see if you have a different voltage? if you still get low voltage this way, you might need to look and follow the pin 12 routing. Pin 11 also shows to come from ignition 1 source. check it in the same manor too
 
Probed pin 7 as ground and pin 11. Good solid 12 Volts

Probed 7 as ground and pin 12 for power I got 9 volts

Did it a second and third time and now reading nothing

Used frame as ground aswell and ground direct from battery.


Tomorrow I’m going to open up the harness from NSBU to top of engine and trace it.

Have power at all fuses aswell







Starting and Charging Systems — 2005 GMC Truck Sierra 3500 2WD V8-6.6L DSL Turbo VIN 2 Service Manual | Operation CHARM

Detailed repair manual for the 2005 GMC Truck Sierra 3500 2WD V8-6.6L DSL Turbo VIN 2.
charm.li
 
I will try and look online for a full diagram to trace pin 12 back to the ignition switch, maybe someone here has a source available. @Denta ?

there might be a distribution area to check somewhere so you can narrow it down and not have to tear into the entire harness.

one thing you can do if the power seems erratic, extend those leads out to where you can watch the meter while in the cab playing with the key switch. it's possible one contact there is not making a good solid connection as you turn the key.
 
See if ether of these electrical books will help you. I couldn't upload them here due to the size of the files but I saved them to my google drive and linked them here. if they will help you, download them and save them to your PC or phone so you can keep them. if the link does not work let me know and I will try uploading them to another file sharing service.

Diagrams - Google Drive

drive.google.com drive.google.com

Edit, I also found this on DP. there might be something here too.

www.dieselplace.com

Info: - 1999-2006 GM Medium Duty Electrical Manuals

cc
www.dieselplace.com www.dieselplace.com
 
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