Cadillac Repair: 1996 caddi STS, wheel sensors, terry howell

Question
Hey Bill, i have this caddi(96 STS 4.6 NTHSTR)Traction control light is on apparently causing ABS to kick out and turn mil on.Both ABS & trac control lights are on.I scanned the pcm for abs codes but none are present . This is confusing with the mil on.I borrowed a newer scan tool from a brother shop and got the same results.Tryed clearing abs codes aqnyway,no luck.Checked VSS and all 4 wheel sensors and all appear to be functioning properly and readings correspond with each other . No various speed changes between sensors.Checked fuses in all three compartments(hood,dash,& trunk)Tryed to overide with manual trac button in glove box with no success.My finding say the system should reset at every start up any way.LIghts do not go off at any time since they appeared.I installed a rear seal in engine,tranny had just been done 1 week earlier.I checked all connections, for days even, all connections are good.Car did not have problem after repair.Had trouble overheating and during that time af try outs is when light appeared.Over heating was caused by an air pocket  and has not given any more problems however i need to satisfy the light problem before i can return to customer who is getting impaitiant.I would greatly apprteciate any help you could lend in this matter.No DTCs for engine present eitherand service engine is not on.
                         Sincerly thanks again
                          Terry Howell DBA. Carolina onsite

Answer
Hi Terry,

       There are at least 9 modules that can store trouble codes on this car and in order to read their codes you need to go into that computor or module. The only codes that will come out of the PCM are the PCM codes. SO since the ABS/Trac light /message is on you need to have a scan tool capable of reading the ABS/Traction control module. And the scanners that are sold by parts stores just won't do the job I'm afraid.

      Once you access the ABS/Traction control module with a professional scan tool programmed for reading those codes you can read the code(s) that turned on the light and know what to fix. Bill