Gm Tuning Encrypted Differently

MHeffe · March 10, 2008

This was on another board concerning GM tuning.....thought you may want to know this.

It was concerning an '06 Trailblazer SS. 6.0, with multiple engine/piston failure in Ca.

In investigating the failures, engineering started to look into the possibility of aftermarket/re-written calibrations, even though the cal id # shown in data was current.

After many repeated attempts by engineering to "decipher" the internals of the program, and months of begging and pleading from Powertrain on this and other "unexplainable" failures, the Delphi and GM (software) engineers finally decided to allow Powertrain engineering access to the actual software programming.

What that means is FOR THE FIRST TIME, GM Powertrain Engineering can look at actual parameters in each subsection of programming, and make side-by-side comparisons of "factory" vs "as programmed"....

Now, what does that mean?

Until TODAY GM Powertrain Engineering could not SEE every individual, specific change...bits and bytes...in every part of a program. They had no way to PROVE a calibration change...except for Cal ID#...and then, they could NOT deny major warranty work if challenged (court/attorney) or Arbitration Board.

It was impossible for GM to prove anything except for speculation...

BUT, with Delphi and GM's Computer Programming/software changes, they will have complete access to comparitive data.....

Because of this, they were able to PROVE this truck had changes to torque limits, spark retard/advance, fuel block counts, evap turned off, egr ramp profile changes, rpm limits raised, a/c command limits blocked, ect....and WON in front of an arbitration board.

This has already had fall-out inside GM. Apparently, winning this case PROVED to GM heirarchy that changes were needed in programming systems. Due to the # and frequency of failures concerning "suspect" programming changes...they have already started to develop a new system to debut in (supposedly) late '08 and '09 vehicles.

The new software will be encrypted differently, have "rolling" changes to encryption, and store values for only 10 software changes or updates...any and all CHANGES to the software will be stored seperately in memory...so comparisons can be made in case of a major component failure. After 10 changes, the ecm will "lock" and operate only on the original software cal. This feature is supposedly to prevent someone from "storing" and "re-loading" an original program. If you were to "rewrite" a program, it would store the original data, then the changed data, and then any re-writes of the original program.

All this would be retreivable by accessing the ALDL and requesting the changes to compare.

Also, he mentioned that, starting in mid May/June, ALL '07 and later vehicles returning for any warranty work that involve connecting to the factory TIS programming system will AUTOMATICALLY have ALL accessible computers/modules checked and verified for any needed updates.....SO, if you have a "hot" pcm recal, it will notify GM and Dealer personel of the "needed" changes....and possibly REQUIRE dealers to recalibrate any changed stuff.

And YES, its legal.

It falls under the Federal Emissions Laws. The factory can, at any time a vehicle is being serviced, check/verify/change ANY and ALL emissions devices it deems necessary, so long as those changes have been verified by the EPA. If it can make a change in tailpipe emissions, they are bound by law to make it work as produced.