hi have a c250 w205 keep getting engine light come car doesnt go into limp mode plug in obd reader its saying exhaust gas tempture sensor bank 1 sensor no 3 can anyone point me the right direction were the senor is located i have changed 2 so far reset the light and after 160 miles bang light back on with same code . i have changed the one thats on top of the cat and the one below the cat cheers