Reprogramming an EBCM

[Motor City Rick]

Here is my issue:

 

About 18 months ago I changed my rear axle ratio from a 4.10 to a 3.08 (2 wheel drive). Knowing the ECM had to be reprogrammed for the axle change, I sent out the ECM for an off vehicle reprogramming. After the reprogramming the speedometer accuracy / driveability is perfect throughout the speed range. The person who did the ECM reprogramming, stated he could not reprogram the EBCM.

 

Looking through my 2001 GMC ST service manuals (3 of them) the ECM also sends a speed pulse signal to the EBCM circuit 1827, terminal B1. With the changes I made so far, this generates a code of P0238, Vehicle Wheel Speed Mismatch (no other codes present) along with the ABS / Brake light coming on after the first mile of driving.

 

I fully understand all the concepts, diagnostics and needed corrections to this issue, but here is my question:

 

Who in North America can reprogram this EBCM to have it recognize that this vehicle has a 3.08 axle instead of a 4.10 ???

 

I know somebody will say take it to the dealer and use a Tech 2 for the reprogramming. I have approached 10 plus Detroit area dealers over the last 18 months and they tell me my "truck is too old", or they will only be able to program what is assigned to the VIN number. The performance shops in southeastern Michigan are also clueless on what to do, they tell me to pull the fuses.

 

I cannot believe I'm the only person in North America that has done this.

 

Can anybody in this forum suggest a place / person who has the capacity to make this software change within this EBCM???