I have a 96 S500 so I don't know if it helps but here goes.
If my car sat overnight, when I started it both the EPC and ASR lights came on on the dashboard and the car was in limp home mode. If I restarted it again and again(up to 30 times) eventually, the light went out and I was off and running.
Diagnostic showed code 1580 EA/CC/ISC actuator.
They replaced the "slide actuator" and I've since been trouble free.
It sounds like you may have been down this path already, but I hope this might be someplace else to look if you don't get better advice somewhere else.