P0140 and P0160 Help
 

HI. Hope someone can help. I have a 2003 E320 W211 with 125000 miles on it. I am getting a P0140 and P0160 CEL (O2 Sensor Circuit No Activity Detected Bank 1 & 2, Sensor 1
So far I have changes the O2 sensors 3 different times with 3 different manufacurers (bosch and genuine Mercedes included).....No change.
I replaced the passenger side CAT pipe ( because it was making noise when banging on the cat....assuming it was bad) with a Walker...perfect fit! .....No change. The only thing else I can think of is the wiring or the ECM. I dont think its the ECM because she runs perfect. Smooth as can be with good gas mileage. Any one seen this before or have any suggestions would be much appreciated.!