7730 Vss signal processing

[K.E.T.]

I think I've learned that the 7730 ECM, depending on the car in which it is 
installed, handles the Vss signal two ways:

A) Raw Vss signal from transmission sensor input on pins B9 & B10, and 
outputs signals for 4000p/mi on pin B11and a 2000 p/mi  on pin C1
   OR
B) Accepts a 4000 p/mi signal from an external signal buffer (yellow box) 
on pin C6

 From experience, if the MEMCAL is expecting option B, but the car is wired 
for option A, a digital speedometer reads much higher than actual speed.

Question: Has anyone found the locations in the MEMCAL that control how the 
ECM handles the Vss signal. I want to change transmission Vss sensors, but 
it looks like I will need to hack the MEMCAL to make it all work. I need to 
decide if I should even attempt it, or leave it alone.  Changing the MEMCAL 
to one from a different vehicle is not an option; too many other vehicle 
specific parameters would be affected. I have the capability to read, edit 
and burn a MEMCAL, but have no experience disassembling the code. I don't 
expect anyone to "do the mod for me," but was sure hoping not to have to 
reinvent the wheel.

Thanks for any help!
Karl

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