Once again helping a friend -2001-C240
 

So it has been making noise, I tracked it down to a leaking PS pump, pretty easy fix. But I have been driving it awhile and the check engine light came on, then her ESP nonfunction light came on . They may have been on , not sure. But the thing runs strong, no issues I can tell
Any advice? IT has 79K on the clock , Do I need to go to a dealer to have it plugged in ??

You can read engine codes thru ODB2 but the ESP codes will require a MB scanner.

thanks