Hi guys,

I have trouble doing checksums on the OPEL/(Vauxhall) Astra files, the do not seem to get reckognized in any program what so ever.
Also I would like to learn a method for doing checksum manualy, like calculating it.
Or at least KNOW some theory behind the wildly known/feared checksums.

Kind Regards

Doesn't your tool do it?

What tool are you using?

Sorry forgot to include the original file.

I only have free winols, tunerpro and clone mpps cable(also does checksum corrections presumably)

I Found a piece of software in a post on this forum.

checksum-corrector-t1227

It states that when I input the file above, there is One zone to check, and 0 corrections (because it the ORI file)

Could it be correct that there is only 1 checksum zone? This is why I'd like to know more about checksums

Guys for the sake of future readers.
I think after this post a lock can be placed on the topic, for my question has been answered.

For the Opel Astra 1600 Delco Multec S BNLA, BNHJ, BPUK, BRNZ the checksum location is 0x3806 2 bytes. Sum of 0x3808 to 0xFFFF
(other computer types I do not have the ori file)
Also confirmed on Opel Tigra 1400 BRNW file

I do future checksum correction manually with HxD Hex editor.

Instructions:
- Open file
- Ctrl + E
Start offset: 3808
End offset: FFFF
Press Ok

- Press Analysis
- Press Checksums
- Select Checksums-16
- Press OK
- Note the 4 character Hex written under the column "Checksums"
-Ctrl + G
Offset: 3806
Press Ok

- And check or correct your Checksum