I have a 97 e320 with 86000 miles. service engine electronics light and service engine light came on last week. pulled codes and got a 133, and a 140. both related to 02 sensors. relpaced both with new ones erased codes driving a few miles later and same thing happened. What else could it be???

There are a number of O2 sensor codes, that will fail the sensor for capability.

The most common codes are for the simple fact that the sensor stays at one voltage for too long. It does this when things are broke, just about anything. An O2 sensor failing for this reason is just saying it isn't running properly.

The next step is more info.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

thanks steve for your reply, whith the code reader pulling codes 133 and 140, and knowing that the 02 sensors are in fact good where would you start??