94 s420 check eng, lite won,t stay out,
 

I HAVE A 94 S420 .TOOK IT TO THE DEALER, HAD AND O2 ,QXGENS SENOR REPLACE,,AND EGR,, SILANOR, REPLACE, AND THEY RE, SET MY COMPTER, CHECK ENG, LITE WENT RIGTH OUT BY THE TIME I DROVE ABOUT25,MILE TO BACK HOME TRUN THE CAR OFF ,,,RE,STARTED THE CAR MY CHECK ENG,, LITE CAME BACK ON RETRUN BACK TO MB,,SHOP THEY CHECK OUT COMPTER,,,AND TOLD ME THEY COULD NOT FIND ANY THING WRONG ,,,SO THEY CLEAR THE COMP,,,AGAIN,,, SOON AS I GOT BACK HOME IT CAME BACK ON CHECK ENG,,,,,LITE ANY HAS EVER HAD THIS HAPPEN TO THEM,,,,TELL WHAT TO DO ABOUT THIS LITE,,,,, THANK,S MELDWYER ,,,,94,,,S420

Check the wiring harness...