what does the Bas/Esp light mean and what do i do on 2005 Mercedes-Benz ML350

baught it this way dont know much about it

Asked by for the 2005 Mercedes-Benz ML350
get module scanned for codes and post so we can adv.
my scanner shows codes po 121 po161 po 400 po 141 it doesnt throttle up untill peddle is 1/4 way down then races up to high rpm
po121 n/a in all data po161 left 02 sensor heater issues po400 egr issues po141 rt o2 heater issues. seek proper diag and repair as this will get exp if you start repl parts at will