COS for 2006 OS

[MoTruck]

I have a 2006 2500hd 6.0 with 12587811 OS. I know that there is not a COS for this number. However, there is a COS for a 2005 OS 12592618. This operating system was used on the same configuration truck in 2005. Can a 2006 be programmed back to this OS, to utilize the corresponding COS 051200xx? Thanks.

[dc_justin]

Give it a try and see. I've tried this on a 2006 4.8L truck and there were some problems with the ETC. Ended up having to go back to the stock 2006 OS.

Justin

[MoTruck]

Thanks for the reply. I did notice that the tune file is slightly smaller on the 2005 vs. 2006 OS, 753kb vs 773kb. I am not sure what is missing.

[MoTruck]

After researching it a little more, I bet your ETC problem was in the tables. The 2006 tables I have are 25%-35% lower than the 2005 tables. Both tables apply to a 6.0 2500hd. I bet this much difference created a problem with the ETC. Did you have any problem re-flashing back to the original operating system? I want to try it, but not fry my ECM in the process. As long as I can get back to the original program, I am up for a challenge. I just remember a big warning about messing with the ETC, and locking up the ECM. Thanks for the help.

[dc_justin]

After researching it a little more, I bet your ETC problem was in the tables. The 2006 tables I have are 25%-35% lower than the 2005 tables. Both tables apply to a 6.0 2500hd. I bet this much difference created a problem with the ETC. Did you have any problem re-flashing back to the original operating system? I want to try it, but not fry my ECM in the process. As long as I can get back to the original program, I am up for a challenge. I just remember a big warning about messing with the ETC, and locking up the ECM. Thanks for the help.
Nope, no problems reverting back to stock OS. It's more than just the etc table values though, as I tried values that matched both the original Calibration and ones that matched the donor tune. Both times, the truck would fault just at the point that boost was made... very annoying. Decided to give up, owner sold the 2 bar map and is happily droving with stock OS and 10psi on his 4.8

[MoTruck]

Do you think it was a boost related problem? I am not running any forced induction yet. I am just trying to learn as much tuning stuff as I can, before taking the boosted leap. Thanks.

[dc_justin]

Do you think it was a boost related problem? I am not running any forced induction yet. I am just trying to learn as much tuning stuff as I can, before taking the boosted leap. Thanks.

Nah, it would have done the same thing if it wasn't boosted.

Justin

[MoTruck]

I tried flashing back to the 2005 OS. I ended up with the same problem. I kept getting a lost communications with the TAC code. There must be something somewhat different on the TAC system on these trucks. Thanks for the help.