Australian GMH 16176424 check sum error

steve3800 · Post by **steve3800** » Wed Mar 08, 2006 10:00 pm

Hi,

I am having a problem with file editing and the check sum,
If I extract the bin file from the eprom 27c512 and program another, no problem, the new eprom works fine. If I hex edit the file and change any data, the eprom will not work and the computer returns code 51, limp home mode.

Cam anybody assist me with how to calculate the correct check sum .

I have tried Tunerpro however i get the same problem. If I open a bin, and then save the bin without any modification i get a check sum error code 51.

]The ECU file has the following info :

Constant 4: KKPGMID: Check sum $5000 through $ffff */
/*|| The checksum is the sum of all values from 5000 to FFFF.
EXCEPT for the area 6000 to 6008 inclusive.

As Tuner Pro cannot exclude an area in its calculation manual editing of the checksum is needed.
The sum of this area must be subtracted from checksum TunerPro calculates and then manually added to the file with a hex editor.
To avoid this problem "AA" can be inserted in the constant "KKKPGMID" (Program ID) to bypass the checksum routine. ||*/[/b]

I have no idea how to do this or how to calculate the corect check sum, inserting AA gives the same error.

thanks.

Post by **Mangus** » Wed Mar 08, 2006 10:37 pm

Figure out where exactly that program ID (called the "mask ID") and open the bin in a hex editor and enter 0xAA at that location. That will disable your checksum.

Can you send me your ECU? (address in signature)

steve3800 · Post by **steve3800** » Thu Mar 09, 2006 1:38 am

Thanks for the reply,
I have emailed the file

steve

adrian · Post by **adrian** » Sat Mar 11, 2006 2:47 pm

Steve
I mentioned this problem some time ago here [url]http://www.supportfitness.com/tunerprof ... ic.php?t=2[/url] but I don't think there was any resolution except for manually calculating the checksum.
I've used the XDF you're using many times with no problems when inserting AA to KKKPGMID. Are you sure Tunerpro is not inserting a recalculated checksum into this area?
You might try deleting the "imported checksum" in the "XDF header info" area.
I think the checksum was imported when I converted it from an ECU file.
Cheers,
Adrian

steve3800 · Post by **steve3800** » Mon Mar 13, 2006 4:42 am

Thanks Adrian,
yes it was inserting the incorect checksum
I have found the correct loc for AA and it works great, ( with help from the forum)

I was having so many problems due to the engine tuner that originaly set the eprom program uses his own code, so no definition is able to work. ( I was told this by another Programmer)
I have since downloaded a stock program $11 ( thanks Mark Mansur for the advise) and modified the ve tables for 2 bar Map.

Well the engines has performed better than ever ( after 15 mods to the tables and many more to go)

I do have one question if anybody can assist,

Can I modify the Map tables, at the moment they read 20, 30, 40, 50, 60 ,70, 75,80,85,90,95,100 KPA

Can I change this to 20, 30,40,45,50,55,60,65,70,80,90,100 KPA
so i have a finer scale between 40 and 70 kpa which is the vacume to boost area where the engine spends most of its time.
If i can change this, will all tables that use MAP need the same scale.

Thanks
steve