Anyone seen a mask named "AA" ?

**EagleMark** · 03-24-2011

I have an aftermarket chip that came in a 1227747 ECM and in the CodeMask it says AA when opening the ship with $42. All the information looks correct with $42...

**Six_Shooter** · 03-25-2011

It'll be $42, since that's the only mask (that I'm aware of) that runs in the '7747.

the "AA" is to disable checksum. One of two things have happened, either the person that made that chip didn't have a proper checksum calculation program, or they were using the bin while emulating, disabling checksum, which is require for emulation and didn't change it back.

**EagleMark** · 03-25-2011

Well I wonder how good this chip is now? Do you know where checksum should be?

EDIT: I thought this bin is the one loaded in the truck ECM... will the bin work in the ECM without the checksum? When it get's here I'll copy the bin first to see what it says...

**RobertISaar** · 03-25-2011

yeah, the mask ID of $AA is one of the GM code engineer's workaround back in the day to disable the checksum for whatever reason, maybe for testing new algorithm or calibrations, whatever...

**dave w** · 03-27-2011

While we are on the topic of CodeMask AA. I just encountered a CodeMask AA. I am wondering if I can change the codemask to 42? The $42 .bin file is from Howell EFI, it's for an AMC 360 / Fuel Only. Here are the screen shots I have.

dave w

**Six_Shooter** · 03-27-2011

You can set it to 42, but it won't change anything in the way the vehicle runs.

**EagleMark** · 03-27-2011

I have a Howell chip from a 258 around here somewhere I will have to dig up and see if they do the same on it... coincedene is the one I started this thread from came from another aftermarket company, it came with a complete system the guy biught years ago...