I have a 2005 GMC with a build date of 07/04. I took it to my local GMC dealer today with 3500 miles on the clock because my MAF sensor had a crack in it. Simple enough .... but I thought while it was there I would ask them to update to the current ECM flash. First thing that comes out of the service managers mouth is "that will void your warranty". Hmm I say, "you are telling me it will void my warranty if you hook a techII to my truck and load the latest version of code from GM?" So, he back peddles and gets a mechanic to talk to me about why I want to have this done. I tell him there have been various problems with Duramax trucks overheating while pulling heavy weights at altitude and some people have reported the latest code has helped the problem. The mechanic proceeds to tell me the latest code wont change anything but transmission shift points and he has never heard of any Duramax running hot. I tell him there have been several, several reports of trucks getting hot while towing and that I am planning a trip to Colorado in the next few months pulling 12,000lbs and want to do everything possible to ensure I do not have any problems. They tell me they can’t update the flash unless I have problems.



I LOVE DEALERS.



I think this has become my biggest pet peeve .... people who are ignorant within their own profession.

Tell them you have the low speed surge and want a reflash to get it resolved. If you do a search for updates you will be able to come up with all sorts of issue to force the reflash.

I was also told the very same thing as you. The reason is "GM won't pay for a simple re-flash unless there is a problem". I said OK and the very next week I had a couple symptoms and the re-flash was done, no problem.
Dan

And GM wonders why they're going under...