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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 15201
Experience:  GM Grand Master Technician 2007. 14 years experience.
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I am working on a 2004 Chevrolet 2500 HD. It has a Duramax

Customer Question

I am working on a 2004 Chevrolet 2500 HD. It has a Duramax diesel and Allison Transmission.
-The PRND indicator will not show what gear it is in.
-The transmission is in limp mode, stuck in 3rd gear but reverse works fine.
-I replaced the NSBU switch and the connectors that go into it.
-The trans fluid is at the correct level.
-I tried to scan it for codes but my scanner will not connect. I don't know if my scanner is not compatible with that truck, but it is supposed to work on all vehicles from 1996-present.
-The OBD port has four wires going to it, Signal ground, chassis ground, battery power, and bus line. It has power, the grounds were about 230 ohms so i grounded them to the frame and now they are 0 ohms. The only thing I don't know how to test is the bus line.
-I checked every fuse with a multimeter, in the cab and under the hood.
-I found some chewed wires in the under hood fuse box, so I pulled it all apart and fixed three wires that were partially chewed through. Every other wire looked perfect. The radio was not working, but after that it started working great.
Any help would be appreciated.
Submitted: 1 year ago.
Category: Chevy
Expert:  Daniel Jones replied 1 year ago.

Hello. Welcome to the site. Thanks for coming. I'm ***** *****.
I'm here to provide as much information and insight as I can, to best answer your question.

Have you checked for any codes in the system?

What is your VIN#?

Do you have any codes in the engine system?

Thank you for posting your question.

Your business is very valuable to us.
Thank You
***** *****

Customer: replied 1 year ago.
I tried to check for codes but neither of my scanners will connect.
A friend is bringing over two more scanners to see if they will work.
I will get the VIN and post back.