I have a question about a checksum message
I down loaded the .bin file from my chip and opened it up in the tunercat edditor, a message popped up that said (the selected .bin file has been modified and the checksum has been disabled).
Is this a problem?
If I make changes to the file and reburn my chip will It work ok?

Thanks

------------------
Louis
Convertable
92 Z28 305tpi Auto w/Paxton, Ram air mod,Water methanol inj.,52mm T/B,ASM Large tube runners, ported upper & lower intakes,AFPR,23# injectors,1.6 roller rockers,slp tri-y headers,3in. cat,3in. gale banks cat back system,3.42 gears,and much more.
http://www.lbsz28blown.cz28.com

 

The checksum is used by the ecm to verify the eprom. As I understand it, if the checksum is incorrect the ecm will either give you an SES code (best case) or not work (worst case).

I cannot comment about the "disabled". I don't believe I have seen that feature in TunerCat. I also don't know if TunerCat will fix it as I do not know if TunerCat computes the new checksum by 1) determining the effects of the changes you made and adjusts the checksum accordingly "differential method" or 2) completely recalculates it "recalc". If it completely recalculates it, its a non-issue.

TunerCat does have a program to recalcualte the checksum for $20.00.

Why not drop TunerCat an e-mail and ask them how their editor calcuates the checksum. Worst case, you can purchase their CheckSum recalc.

 

Well.. the .bin has a flag at a certain adresss that tells the ECM whether or not to check for the correct checksum. In your case that flag is set to "no" therefore TunerCat gave you that message. I don't understand how that can happen with a STOCK .bin but I guess you never know. TunerCat in this case won't recalculate the checksom because the flag is set to "no". I think you should download winbin and the appropriate .ecu file and turn the flag back on. Or just don't worry about it... it's not gonna hurt anything.

 

Can the checksum be disabled somehow so you can put any chip it and have it work?