Service stability system,service brake assistance,service steering and t/c light
 

Every time I turn my car on, the dash lights up with all of these errors.
It also doesn't think it is in Park sometimes when I shut off the car. I ran diagnostics and got the following error codes: P0856, P1793, U0121. I've been researching for hours and only found generic error code descriptions, but people seem to think the problem may be the wheel hub. Another forum suggested it could be as simple as finding and replacing a bad fuse that may have shorted out along with disconnecting the battery to reset the codes. Unplugging the battery didn't work, and I have no idea which fuse could be bad, but I'd really rather not pay a dealer for hours of labor to figure out the problem and then overpay for whatever parts I need. Please help!

I hope there is still someone reading this forum. I have a 2009 cts v6 and the ABS and stability system lights came without codes. The car stops without issue and the tracking system says its off. I can't tell any real difference on handling. What can cause this issue? please help this is my 1st caddy and I want to treat her right.

Sounds like you have a hub assembly that has failed, but I would wait for a tech certified member to chime in with a response. If you do end up replacing one, DON'T go the "el cheapo" route- the inexpensive units have the life expectancy of a state fair goldfish.

Make sure master cylinder fluid level is not low. Not all scanners will read ABS or Stability system codes. Traction off is related to ABS most likely. You might have codes checked at dealer.

Service Stability System
 

Had this problem with my 2008 STS V as well as other messages including 0 tire pressure and tire pressure monitor not working. Turned out to be hub assembly. Even the message saying Lane Departure System not available (car does not have it) is no longer displayed. Correct diagnostics from Massey Cadillac in Orlando.

HA! THE CODE READS c0045, translating to the left rear speed sensor. However, since I changed the sensor the code persists, the wheel hub shows no indication of being bad, e.g. noise or rumble. Is there a way to reset the code without having a code reader?

At first
 

The diagnosis for mine was also the speed sensor error. But the cure was not a new sensor, it was a new hub. Yep, a bunch more bucks. But it's wonderful not having your car 'yell' out you every day and having traction control back is welcomed.

I have just purchased a 2005 STS 4.6L V8 rear wheel drive. I see 2 error messages, Brake Assist is one and TTY is the other. I see from reading this forum what the Brake Asst is likely to be. In my mind TTY is about telephone stuff? I didn't know the car had that capability? Is this pre blue tooth technology?

ABS steering assist and traction control lights came on and wont go away after i changed my battery to a new one the old one wasnt holding charge ive tryed taking pos terminal off and holding the brake and a few other tricks......ANY IDEAS...i dont feel there is anything that needs to be replaced due to it being fine before the battery swap