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2004 hummer h2 serviceis staying on the info screen i have…

2004 hummer h2 service*****is...

2004 hummer h2 service*****is staying on the info screen i have replaced the transfer case motor i am still getting codes c0306 c0327 and c0388

Mechanic's Assistant: Just to clarify, what's the exact code? And have you tried to reset it?

Yes i have tried to erase the codes they are c0306 c0327 and c0388

Mechanic's Assistant: Are you fixing your H2 yourself? What have you tried so far?

Yes i am fixing it myself i am an heavy truck mechanic i have replaced the transfer case motor as referanced in the first message

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Answered in 10 hours by:
3/26/2018
Chris (aka- Moose)
Chris (aka- Moose), GMC Technician
Category: GM
Satisfied Customers: 52,654
Experience: 16 years of experience
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Welcome, I'm Chris (aka-Moose).

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Do you have or have you done any of the tests related to these codes?

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Customer reply replied 3 months ago
I don't know about any tests what are you talking about? I ran the codes my scanner in 2 cases said most likelyfix tcase motor so i replaced ir
Customer reply replied 3 months ago
No experience with transfer cases

Here is what the code state to do. Can you do these tests?

https://www.dropbox.com/s/hm9u84q7rjwx4e3/0306.pdf?dl=0

https://www.dropbox.com/s/pn7s6l4k4o7a9uq/0327.pdf?dl=0

https://www.dropbox.com/s/o9hb8id96llbgg7/0388.pdf?dl=0

Based on a new shift motor is on the vehicle. If I were put in the situation to have to guess, it would be a wiring concern.

You now will see a rating scale 1=bad to-5=excellent because I have posted a full or partial answer instead of an info request. When you rate I get a portion of the deposit you made, no rating means you still paid, but I earn nothing. My goal is understanding your question, and addressing it in full detail. In return, receiving a 5-star rating. Rating does not close the post or stop the conversation. Please keep in contact and reply as much as needed. Thanks, Chris

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Customer reply replied 3 months ago
My scan tool will not read the encoder circuit it is not a fuction of the tool basic 300 scanner this is called for in first diagnostic test what do i do
Customer reply replied 3 months ago
Also what are the wire colors for the a and b circuits i don't have a wiring diagram

Here is a wire diagram.

https://www.dropbox.com/s/52ioz535uyb00fr/humtran.pdf?dl=0

Any tests you can not do because lack of tools, skip over those to see if you can get results doing the other tests.

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Customer reply replied 3 months ago
Ok when key is on no power at either wire i went ahead and checked the trc and 4wd fuses shown on diagram they are good

What code are you diagnosing and what step are you up to so I can follow along and respond accurately.

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Customer reply replied 3 months ago
Steps 6 7 8 code 0306

Steps 6-7-8 are checking to see if the red and black wires are good from the shift motor to the module. You are wanting to see if the wires are shorted to each other or to other wires or the chassis. You are not testing to see if there is voltage on these wires with the key on.

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Customer reply replied 3 months ago
Ok i am not sure how to test if wires are shorted together what would you recommend i test to get things moving
Customer reply replied 3 months ago
Tested both wires running into coil on rear end meeter shows 1\ open circuit after reading the dbox docs i am thinking it is transfer case control module is there a way to test it with a dmm and tell if it is bad or not don't see any wire damage at all on the vehicle i have my doubts that it has ever been off road. Also is there a way to test the encoder without scan tool

To test if wires are shorted together you ohm test both of them. If they are shorted the reading will be 0.0.

The only way to test the module is via scan tool and by all the tests above to see if the module is not doing what it should.

Encoder testing can be done with a DVOM but no where near as accurate as a scan tool.

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Customer reply replied 3 months ago
When ohms testing get open reading\1 on both wires

That test passes

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Customer reply replied 3 months ago
is the transfer case control module the problem? Is it a wiring issue? Is it the switch?

Have you completed all the tests after this ohm test?

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Customer reply replied 3 months ago
Open\1 is the result of steps 6 7 8 shorted together a circuit and b circuit the way i am interpreting this sheet leads me to believe that the problem is the transfer case control module am i correct?

When you complete step 8 it says to go to step 10. Step 10 says to replace the module.

You now will see a rating scale 1=bad to-5=excellent because I have posted a full or partial answer instead of an info request. When you rate I get a portion of the deposit you made, no rating means you still paid, but I earn nothing. My goal is understanding your question, and addressing it in full detail. In return, receiving a 5-star rating. Rating does not close the post or stop the conversation. Please keep in contact and reply as much as needed. Thanks, Chris

Chris (aka- Moose)
Chris (aka- Moose), GMC Technician
Category: GM
Satisfied Customers: 52,654
Experience: 16 years of experience
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Chris (aka- Moose) and 87 other GM Specialists are ready to help you
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Customer reply replied 3 months ago
Is that module specific to hummer or is it used in say a 2500 pick up as well ? I will buy a module new tomorrow if necessary but if it crosses with something else that i can find at a junkyard it would be nice cannot find a junkyard anywhere near me with a hummer and i am trying to finish the vehicle. Quickly so i can sell it

I have no way to prove if the 2500 module is the same. I would need a dealer parts tech login to do that and compare part numbers.

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Customer reply replied 3 months ago
should i just call chevy and ask for the part no for say a*****then call hummer and compare?

You can give that a shot.

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Customer reply replied 3 months ago
Is the trans control module behind head light switch see 3 connectors but don't understand how you get it out if not where is it?
Customer reply replied 3 months ago
Transfer case control module
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