03 2500HD 4x4 Duramax/Ally

rileythedog · April 27, 2003

Hello everyone,

I managed to talk my father in law in ordering a 03 Duramax. He took delivery of it last Friday.

As a GM employee I was rather upset that the GM dealer pulled the fuse to the 4X4 so he could drive it. At 35 Kms his service 4X4 came on. The same dealer said they have 4 so far that the 4X4 does not work. GM has no fix yet and there is a bulletin out on it.

Has anyone seen this bulletin or familiar with this problem?

John

Bluedog · April 28, 2003

My 03 D/A started with a constant service 4X4 message at about 300 miles. My dealer replaced the encoder; the message came back within 15 miles, although it was very intermittent. The dealer called a few weeks later and told me to bring it back, they had a new flash for the computer. The message has come back only twice or three times in the last six months. I find that if I turn off the ignition and then restart the engine, the message is gone. I seem to get the message when it cold and wet (rain / snow)... don't know if its really connected.

The 4 wheel drive has always worked fine, even when the message appeared. According to the dealer, GM has put out a bulletin that basically says the encoder sets a code because it goes "to sleep" and when you start the truck the computer doesn't get a response from it. The flash makes the computer a more tolerant of this condition. I have read that GM has yet to issue a real fix, however.

I would ask the dealer to put the fuse back in and see if the message actually comes on. It seems that many people never have a problem, others like me have it every once in a while. If the message does in fact come on, have the dealer read the code and see if it is the encoder, as opposed to a problem with the pushbuttons or other controls. If the encoder is the problem, I think that GM lets them replace it once, along with the computer flash. I wonder if the message came up while they were prepping it, and they decided to pull the fuse instead of fixing it...

Hope this helps,

Mike

BTW -- too many "dogs" here!

Heavy Duty · April 28, 2003

This happened to me a month and a half ago. 2003 GMC 2500HD 6.0L Service 4x4 light would come on, then at about 250 miles, while driving through my neighborhood, the truck went into 4-low with out notice. Luckly at a low speed. Took it in, they pulled the fuse, said it was the encoding motor on the t-case. Its been about 6 weeks, they called and left me a message yesterday, said GM found the problem, and they ordered me the new parts. So this week it should be fixed. But trust me, I will be watching for that light to come back on... $38,000 truck broke at 250 miles, I wont put up with this for very long!! Ill keep you guys up-to-date with part #'s when I get them.

rileythedog · April 28, 2003

Well I talked to the dealer today. The bulletin is # 03-04-21-001(12-43-129) dated Feb 14 03.

The gist of the bulletin is that the encoder is failing due to heat and /or vibration causing fluctuating voltages to the computer. They recomend not replacing the encoder as it may be a temporary fix.

One other new owner had to limp back to the dealer with "4x4 Lockup " in low. They pulled the fuse.

Sounds like we are all on the same page here.

Heavy Duty if you can please post a repair procedure info # so I can forward it to my/his dealer. The service manager is not being to pro-active concerning this.

John

rileythedog · April 30, 2003

If anyone is interested the repair bulletin is # 03-04-21-001A dated April 17 03. Proceedure and parts are listed.

John

May 19, 2003

rileythedog,

I got the 4wd Service light error today. Read in the manual to stop and turn off the truck and then restart if message does not come back. If if does come back take the truck to your nearest dealer. When I shut down and restarted the 4wd service light did not reappear.

How can I find out more information on the bulletin that you have listed?

Thanks in advance

PP