01 SE with 78k miles , the ABS, TCS OFF, and slip light stay on all the time now.
Has anyone had this problem or know the fix ?

 

you prob just ned to reset you ecu. try disconnecting the (-) side of the battery and leave it for about an hour. if it stays on after that than you can begin to get concerned

 

I kept getting the same thing on my fathers 99 GLE. It was two bad coils. They didnt completely fail and would work on and off and thats what triggered the two other warning lights. I would clear the ECU and then a couple of days (sometimes hours) later the lights would come on again. I spent days diagnosing this by the book only to find out that it was the bad coils that were the cause. Good luck.

 

Had the same problem with my 2K SE Auto when I
bought it.....Dealer replaced ingnition coils and alls well
ever since (13K ago).