Why multiple OS's for same year car and ecm

[Chalky]

I basically do tuning on my car so rarely have a need to do anything with other than stock OS. Just curious as to why GM would have so more than one OS for any given model and year?

[gmh308]

I basically do tuning on my car so rarely have a need to do anything with other than stock OS. Just curious as to why GM would have so more than one OS for any given model and year?

You referring to anything specific Chalky? In most cases the OS stays the same in a model year per vehicle. Have seen some exceptions, but not many. Sometimes the OS even spreads across a number of platforms in the same MY.

:cheers:

[Chalky]

No specifics. Just wondering why a model would have more than one OS.

[Gordy M]

It might be different for the Kalifornia ecm and the rest of the world. I know my 2000 vette was a NY (Kalifornia emissions) car and had pup cats, the normal cars did not and both had different OS.

[gmh308]

That is one of the potential major reasons, emissions regulation changes from year to year, and it looks like CA has unique requirements at times.

Other reasons can be production changes in things like sensors for example, change of manufacturer or spec, resolution of bugs, fine tuning of certain areas, revisions, ECM hardware/firmware changes, etc etc.

Have only actually seen this on a G8 in the same MY.

:cheers:

[GMPX]

If you look on the CalID website where they list all the OS's for a particular vehicle it will usually list the reason the OS was replaced.

For example on an E38 -

12616478 - New software to meet plant running change for the LZ4 and LZ8 engines, and proper ethanol content calculation for (LZE) Engine.

The update rate is far higher than it was years ago, I think because the ECM's are now shared over so many platforms. But back in the LS1 days Holden as an example used the same OS for 3 years!, now it seems there is a new one every 3 months.

Cheers,
Ross