Mercedes S430 P0140 and P0160 Fault Codes After Sensor Replacement - No Activity in Bank 1 & 2, Sensor 2

Model: Mercedes S430 Fault Code: P0140 Posted: 2016-03-29 15:55

I recently replaced both oxygen sensors on my Mercedes S430, but after the replacement, the vehicle is now showing P0140 and P0160 fault codes for both banks (Bank 1 and 2) at Sensor 2. The OBD2 system reports 'No Activity' for these sensors. Previously, I had only Bank 1 Sensor 2 with a P0141 and P0161 code indicating an open heater circuit in the heater line. After replacing the sensor on Bank 1, both Bank 1 and Bank 2 Sensor 2 codes appeared. I then replaced both sensors again (returning the faulty one for refund), but the issue persists. The system now shows 'Confirmed' status after less than 10 miles of driving. Can anyone explain why this 'No Activity' error occurs after sensor replacement? Any insights or troubleshooting steps would be greatly appreciated.