The only real way to troubleshoot, is going to require a scan tool to communicate with the EBCM(electronic brake control module). There is no way to determine why the light is on without extracting the trouble codes. I am not sure if a parts store can scan trouble codes, since most generic code readers only extract powertrain codes. I did a check for service bulletins, the only one that comes up is unwanted ABS activation, this would be a feel, and you would have no visual indication.
Friday, March 5th, 2010 AT 9:26 PM