Duramax 4WD Issue

MaxComp88B

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Mar 30, 2022
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My truck keeps getting a service 4WD thing on the dash. I take it in to have it relearned and it only works for like a few weeks. I do have a hub going out but in the front end everything else checks out even the fluid as it has been changed. So is that why it happens? I am tired of paying 130 every so often to get it relearned.
 

2004LB7

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Sounds like the hub is causing it. Sensor in the hub is probably not reading right. The codes would be nice
 

MaxComp88B

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Mar 30, 2022
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No codes other than a glow plug and intake heater. Occasionally I get a brake switch one but that’s once in a while.
 

2004LB7

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You'll need a different code reader that can access the other modules. Generic ones will usually only read the ECM
 
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MaxComp88B

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Mar 30, 2022
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Will the code readers at o rileys be able to read codes that are other than ecm? Just need it scanned real fast. I will look into a good scanner though. I have an Edge which works great but I need to be able to read more codes.
 

MaxComp88B

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Mar 30, 2022
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Got a dealership to do a code read today. They did the free one not the one that cost 60 bucks as I had to have an appointment. C0569
From what I see on internet it could be a bad sensor, a short, a bad switch or anything. Any help or do I need to pay for the dang 60 dollar scan and get more info?
 

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SoCalMike

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Dec 12, 2010
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Have you checked the ground wires? Do you hear the encoder motor trying to switch when you go from 2wd to 4H? Ground wires are under the drivers door on the frame. Make sure they have good contact. Take them off and clean them to make sure. You can also check voltage at the actuator connector on the front diff. Make sure you have ground there also.

Sent from my SM-G996U using Tapatalk
 
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MaxComp88B

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Mar 30, 2022
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Have you checked the ground wires? Do you hear the encoder motor trying to switch when you go from 2wd to 4H? Ground wires are under the drivers door on the frame. Make sure they have good contact. Take them off and clean them to make sure. You can also check voltage at the actuator connector on the front diff. Make sure you have ground there also.

Sent from my SM-G996U using Tapatalk
I turn the switch and it doesnt even blink or do anything. I will check grounds. I plan on checking all the wires soon. I will definitely clean the grounds.
 

JoshH

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Looks like you need to do a relearn on the 4wd encoder motor.