brake trac light need advice co550

[dnakohrmann]

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

[BNaylor]

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.