Help: need help bad PLEASE

[Aaronbryant89]

first off i have a 2006 lbz has 206k all stock execpt k&n intake on it havent had it very long was great at first now having weird problems

it all started one night (was cold but not sure that makes a difference) went to start and thrown a code lost communication with trans .. i reset and seemed to drive just fine .. went a couple days and figured it was just something weird going on... well a few days later it did it again but still drove just fine

about a week after that started seeing voltage codes along with the original codes

today went to start it and it went to start and stalled .. tryed again and did same thing .. put my foot on and gas pedal and started right up throwing alot of codes

figured maybe its a weak battery and got them load tested and seemed weak so i went and bought some nice agm batterys for it and still same thing and it doesnt matter if its out side or in the bay 65 degrees its now doing it every other time trying to start

thought perhaps i had a bad ground

tested at the battery for voltage and had 12.3 resting then checked at fuse block and only have 11.5 with no load i did find a bad ground and fixed thatnow at the fuses i see the same as at the batterys but problem is still their and im not sure where to start now i will post a bunch of pics of all the codes

thank you in advance for any help

 

[Aaronbryant89]

ill post alot more codes tomorrow i gotta get to bed

 

[TeaBagger2006]

Have you checked the alternator? Bad tcm?

 

[THEFERMANATOR]

If you have that big of a voltage drop with no load, you have a serious problem. Find your voltage problem before you go any furthur. Low voltage and stray ac current will wreak havoc on an electrical system(alternators all put out some ac current as no diode trio is perfect. Your batteries dampen and surpress it. With poor connections, your batteries cannot surpress the ac current, then ac current makes it to the trucks electrical system, and solid state controllers hate ac current).

 

[bmc1025]

Remove and clean the grounds on the frame under the drivers door, at least this is where i would start.

 

[Aaronbryant89]

So it's a very good possiblitity that it's still a bad ground somewhere?

I found the wires going to the battery's was very bad.. cleaned and put die electric grease and it did help with voltage lose but still getting the codes

 

[Hot COCOAL]

You checked all the grounds at the bottom of the block too?
You said it was really cold and everything is stock, I'd really look at the grid heater power lead and alternator...stuff that would be loading the system the hardest

 

[Aaronbryant89]

i have not checked all the grounds quite yet ... im about to go buy a haynes manual so i hopefully that tells me where they all all at

i did notice though that when i start it the dash says like 9-10 volts and takes like 30-45 sec and then jumps to 14-15 like it should be

the glow plugs would already be off if its started does the intake heater stay on for a bit after its running?

:dontknow:

 

[SmokeShow]

There should be diagrams of where the grounds are in the GM Specs section of the forum. That GM Specs section is a subsection of the Technical Service Bulletins section which is about 6 sections down from this one. Hopefully that'll save you from buying the manual. :thumb:

 

[Aaronbryant89]

 

[Hot COCOAL]

i have not checked all the grounds quite yet ... im about to go buy a haynes manual so i hopefully that tells me where they all all at

i did notice though that when i start it the dash says like 9-10 volts and takes like 30-45 sec and then jumps to 14-15 like it should be

the glow plugs would already be off if its started does the intake heater stay on for a bit after its running?

:dontknow:

If I recall correctly, not only does the grid heater turn on, key on cold start, it runs intermittently if the intake air temps are too low? I'm not "positive" about that but I believe that's how the grid heater works

As for the glow plugs, when the light goes off is just when the cylinder temps are at temp, I believe the glow plugs do stay on slightly longer after the engine fires...but don't quote me on that one either...



It almost sounds like you need an alternator?
Do you need a New belt, maybe getting some belt slip?
And clean all the connections, positive and negative

The loss of communication to the tcm and all the codes is what gets me, new battery and same issues, right?

Yeah, Id probably test the alternator next...

 

[Awenta]

If I recall correctly, not only does the grid heater turn on, key on cold start, it runs intermittently if the intake air temps are too low? I'm not "positive" about that but I believe that's how the grid heater works

As for the glow plugs, when the light goes off is just when the cylinder temps are at temp, I believe the glow plugs do stay on slightly longer after the engine fires...but don't quote me on that one either...



It almost sounds like you need an alternator?
Do you need a New belt, maybe getting some belt slip?
And clean all the connections, positive and negative

The loss of communication to the tcm and all the codes is what gets me, new battery and same issues, right?

Yeah, Id probably test the alternator next...

Yup they stay on depending how cold it is. I'd also check all the grounds and test the alternator. I wouldn't pay much mind to the rest of the codes for now. These trucks go crazy when you have voltage issues.

I also had a bad radio adapter do all kinds of crazy things to me.

You can get a wiring diagram from gmupfitter that will show you the grounds. They're free.

Sent from my SM-N910V using Tapatalk

 

[Aaronbryant89]

So a little update.. I have tracked down as many grounds as I could find.. I did find 1 pretty bad one and 1 I wanted to clean up just to to be sure.. I also replaced the ignition switch (had the slide in tumbler go bad during doing it and that has a head ache to get out since I could not turn it) but the problem is still their..

 

[Aaronbryant89]

Also went through my scanner to monitor modules and found this... which I'm just gonna guess is the tcm since it reads 0 and that's the one I'm having problems with

 

[Aaronbryant89]

Could somebody tell me everywhere that the tcm gets its power from? That would greatly help alot

 

[Hot COCOAL]

Post #5 should cover what you're looking for
http://www.duramaxdiesels.com/forum/showthread.php?t=11140

 

[Aaronbryant89]

So getting despite and checking all kinds of dumb things before I take it to a dealer and I seen that these 3 fuses inside the cabin never get power at all... I'm not sure what they are linked to buythey say ignition... if somebody has a wiring diagram could u tell me if this is part of the problem? If so where to start? All the fuses under the hood test fine...

I tryed key off... key on accessory... key on ignition. . And it running

And it also started to stall right after it starts up again so the ignition switch hasn't fixed any of the problems =(

I'm definitely lost now and could use some advice.. or does it sound like I'm gonna have to get the tcm changed ? Which I'd very much like to avoid if possible

 

[Hot COCOAL]

So it's a very good possiblitity that it's still a bad ground somewhere?

I found the wires going to the battery's was very bad.. cleaned and put die electric grease and it did help with voltage lose but still getting the codes

Dielectric grease is a "NON CONDUCTIVE" silicone grease... IT IS NOT a conductor and should not be used to "help" an electrical connection, rather its properly used to protect said connection
:hug:

I learned the hard way

 

[Hot COCOAL]

View attachment 41138


So getting despite and checking all kinds of dumb things before I take it to a dealer and I seen that these 3 fuses inside the cabin never get power at all... I'm not sure what they are linked to buythey say ignition... if somebody has a wiring diagram could u tell me if this is part of the problem? If so where to start? All the fuses under the hood test fine...

I tryed key off... key on accessory... key on ignition. . And it running

And it also started to stall right after it starts up again so the ignition switch hasn't fixed any of the problems =(

I'm definitely lost now and could use some advice.. or does it sound like I'm gonna have to get the tcm changed ? Which I'd very much like to avoid if possible

IGN 0 is the TCM
TBC is the Truck Body Controller
VCHMSL or whatever is the fuse for the High mount stop light at the back of your cab, if you have one


The TCM shouldn't "just fail" because it got cold...
Did you or have you jump started this truck? I read that there was a TSB issued on a couple years of the Dmax powered Silverado due to frying the ground to the TCM when jump starting...but I think no matter how you lose the ground your TCM is screwed?

I'm not sure You can really know the TCM is bad until you try to shift it into gear...? I don't know the "tech way" to test one

How cold is it?
Has your fuel gelled?

11.5v shouldn't cause the TCM to freak out, either...pretty sure it has to drop to low 10v range before communications get messed up...

Is your CP3 pulling fuel?
You said it starts and stalls and that it ran with your foot down on the throttle...almost sounds like more of a fuel.related issue than and electrical issue...

 

[Aaronbryant89]

Ok well I have no power to ignition 0