I have a 1997 S420 with the CE light on. I got the usual O2 sensor failed error codes (4 of them on Bank 2) so I had a local shop replace one of them with an OE sensor. The very next day the CE light came back on and now it shows 6 error codes for both Banks – P0153, P0130, P0150, P0156, P0136, P0160. It now says that both O2 sensors are bad! Has anyone experienced something like this before? Any clue as to what’s going on? Thanks in advance for your help!