brake trac light need advice co550

Car is 2004 grand prix gtp and the brake and traction control lights are on intermitently.
When this happens the magnasteer is disabled also. Now I had these same symptoms not long ago and since I have a scanner it was easy to diagnose as a speed sensor, replaced it and all was well. Now same thing is happening but when i hook up the scanner all speed sensors are functioning and the only code is co550(ebtcm malfunction). I want to assume that is the problem but one thing one the scanner catches my eye, it lists speed ring 1-4 and 1-3 say calibrated but 4 says not calibrated. I do not know what this is or what it means. One other thing of interest: I had a leaking brake caliper that I just replaced today and it looks like it has been swamping the hub and speed sensor with brake fluid for some time. Any help would be great, thanks

Other than the wheel sensors common problem area is the EBTCM module and the ABS DTC C0550 probably confirms it. The EBTCM also controls the Magnasteer.