Early E38 vs. New E38.....

[Redline Motorsports]

I know a few of us had an exchange over this a year or so ago but I had to bring it up again in a different light.

Why can't we use a 2009 E38 in a 2007 E38 application of the same model? All sensors are the same as far as pinouts I believe.

I know the TAC module subject comes up but not sure if thats in the ECM or a seperate module like the LS1 ECM's where.

Maybe Ross can chime in and add some insight on why this can't happen.

Thanks

HT

[gmh308]

Its covered in some other posts Howard, but in short, its the way the '09 OS's use an area of the flash that stores variable data. (learn data etc)

06/07/08 all pretty well compatible/similar, but 09 quite different, so when the 08 OS for example reads the 09 data, or vice versa, the E38 "swallows its tongue." (my words). 10 different again apparently.

It only reads the data once...:)

If only it was possible to write that area of flash and reset it...but I guess Ross will know why that cant happen.

[Redline Motorsports]

Definately don't want to beat it to death but.................

As long as pin assignments where the same (which I really don't know if they are..) and you write to a 09 PCM why should anything be different if you switched PCM's?

Why shouldn't it be any different then replacing your computer at home as long as the OS matches the hardware?

I wonder if there are other modules that are effected by this.

[gmh308]

Definately don't want to beat it to death but.................

As long as pin assignments where the same (which I really don't know if they are..) and you write to a 09 PCM why should anything be different if you switched PCM's?

Why shouldn't it be any different then replacing your computer at home as long as the OS matches the hardware?

I wonder if there are other modules that are effected by this.

'09 OS into '09 hardware, and '08 into '08 hardware is fine. From schematics I have seen, the pinouts are identical across the years, unless some odd feature was added/turned on (or deleted) in a later OS. Cant think of one, apart from say an OS that saw AFM added for '09. But that seems to be there in the background on all whether it is used or not.

But...the word "hardware" is probably a little off track. My understanding is that all hardware is pretty well the same, with same hardware OS/bootloader (some '05/06's different on this), but they become an '08 or an '09 once the first vehicle OS is loaded. After that there is no turning back.

But if you are talking an '08 ECM & OS into an '09 car or vice versa, then thats more of a crap shoot. Have definately seen issues where if the OS does not line up with the rest of the modules in the car, odd things happen.

Then again, Chris White added '10 launch control to his '09 Vette, so all the stars lined up on that one, but then trying to add later features to an earlier G8 for example does not go so well.

[GMPX]

Part of the issue is other CAN modules on the bus are usually configured for a specific year. So as a hypothetical example, lets say the desired torque message from the ECM to the TCM is in 'x' format for 2007, then in 2009 they changed the message structure for that torque signal, all the modules in the 2007 model will have no idea what the message format is.

My understanding is at minimal the ECM & TCM years must match as the torque models are different over the years. Simple test, get a 2009 Corvette ECM, use TIS to flash in a stock 2009 program to suit the trans type, plug it in to a 2006 and see what works and doesn't work (eg, what gauges stop, A/C etc).

You have to remember that there is so many modules on the CAN bus these days and most (if not all) are running software to suit particular year models and vehicle configurations.

Just to finish it off, as Ian mentioned, GM changed the structure of some critical area's in the ECM which results in incompatibility between software years. This is not an EFILive issue, if you reflash a 2006 ECM with 2010 software using TIS you will corrupt the ECM, this is why GM now have specific part numbers for the different E38 model years.

Cheers,
Ross

[Redline Motorsports]

Ok so I guess all we need is a MAF patch to extend the MAF to 1500 gms/sec!:hihi:

[GTPprix]

Ok so I guess all we need is a MAF patch to extend the MAF to 1500 gms/sec!:hihi:

I'm running a 2010 E38 in my 2009 Z06 and it works fine BUT my 09 also has all the same systems as the 10 so YMMV.

[Redline Motorsports]

I'm running a 2010 E38 in my 2009 Z06 and it works fine BUT my 09 also has all the same systems as the 10 so YMMV.

Chris why? Launch control?

At least you have the higher resolution MAF range......I guess I'll be scaling to get this 2006 to not bounce off the MAF table!

Howard

[GTPprix]

Part of it yes (small part) as well as the nice higher IFR limits ect :)

[gmh308]

'08's support the larger MAF scaling. :) (except for LS7 :( ).

[GMPX]

Ok so I guess all we need is a MAF patch to extend the MAF to 1500 gms/sec!:hihi:There was two changes, the split MAF table went to 12,200Hz and is limited to 511.9922g/s, in 2008 it changed to a 15,000Hz upper frequency limit and massive g/s limit. Main reason is they went from standard scaling to floating point numbers in 2008, that is a pretty major code change.
So on the older ECM's, even though it might be possible to extend the MAF frequency above 12,200Hz you are still going to be limited by the mathematical limit of the scaling used to get the highest g/s value (511.9922g/s). So there is not a lot of point to extend the frequency range.

Cheers,
Ross

[GMPX]

'08's support the larger MAF scaling. :) (except for LS7 :( ).2008/09 LS7's are still using a 2007 base OS :angel_innocent: , I am talking about 12612281 & 12628988.

[gmh308]

2008/09 LS7's are still using a 2007 base OS :angel_innocent: , I am talking about 12612281 & 12628988.

Yes GM pretty well left the LS7's alone with the split MAF tables :).

[Highlander]

Cant you use an LS3 OS?