Writing to a brand spanking new E37 ECM

[engimuneer]

From what I've gathered, EFILive cannot, nor any other aftermarket tuners, flash a complete file to a brand new ECM. That is what the magical 'Tech 2' Scanner must do.

What are some of the areas that don't get updated or installed with tun & ctd files? I've seen stuff like ETC [electric throttle control] CPU & pin outputs get set and not changed, but wondering how much deeper it goes.

Why can't an OS go backwards compatible if the internals of the ECM are the same? Something must not be getting erased.

Thanks!

[GMPX]

The E37, E38 and E67 ECM's all contain a second CPU that just watches over the Main CPU's throttle decisions. This CPU cannot be read, it's write only, this is why we can't flash it, we can't get the data out of that secondary CPU. The TechII (well, really TIS2WEB) has all these files on their database so they don't need to read the 2nd CPU, they just flash the correct files in to that CPU once they are extracted from GM's on-line database.

There is parts of the ECM's flash we (or TechII) does not write to during a reflash. The flash layout in these ECM's is like so, Bootblock, EEPROM Emulation, OS, Calibrations. In 99% of cases there is no need to ever write to the Boot or EEPROM emulation area's of the flash, that is why we (or TechII) don't, it's risky. Unfortunately the coders at GM changed the layout of the EEPROM emulation areas over various model years, so if you flash an OS that does not match the layout of that area the ECM ends up corrupting it (for good). EFILive spent a fair amount of time adding the OS compatibility check in to the software to ensure you wouldn't flash an OS in to an ECM with an EEPROM Emulation section that didn't match.
That is the very reason why GM have different Service Numbers for the same ECM over a number of model years because the same issue would happen using a TechII.

I have heard on the E38 at least there is a subtle hardware difference between the earlier years and the new ones that results in them reading sensor values wrong.

Hope that helps explain the situation.

Cheers,
Ross

[engimuneer]

Great explanation Ross and thanks for the input.

The most current service number GM is using for the E37 ECM is backwards compatible from 07-11 with the GM dealers initial flash. Unfortunately they will only flash the original (or their 'improved calibration') file to your ECM based on the VIN. This shows they could flash an 09+ system into older models. They just won't unless you have the proper VIN.

[GMPX]

Looking at the files I have here it would appear the 2010 & 2011 V6 truck is the one that would not be backwards compatible. I found this out the hard way :frown:

[engimuneer]

The Silverado V6 should be from a 2009. It did have a different OS & CAL than the 09 Cobalt & HHR files I flashed. I was able to flash onto the 09 Silverado ECM with the 09 Cobalt files and drive the vehicle. Full flashing is what killed the ECM.

[GMPX]

If you could recall what the 'original' OS number was in the ECM and what you full flashed in that would help determine what went wrong.
Unfortunately on all these late ECM's the vehicle year model doesn't mean it's a safe bet. A prime example of this on the E37 is the 2011 HHR is using an OS that is compatible with a 2009 Cobalt, yet a 2010 Silverado V6 is not compatible with either of those. It's a fun task maintaining our inbuilt software compatibility list because there is no logic to how it all works.