I was looking at some data from a handheld Actron Scan Tool, basically looking for an excuse to replace my O2 sensors.

All sensors seemed fine by the volt readings except bank 2, sensor 2, which hung right between .7 and .85 Volts for the minute or less I was watching it (car was already warmed up).

Does that definentally mean the sensor is bad, or is the cat possibly bad, and if it is, why haven't I seen a code?

Thanks

 

Yes your bank 2 o2 needs to be replaced and no I don't know why is hasn't thrown a code yet.

 

Before you start replacing sensors, verify that its actually the sensor that's the problem, or if a problem even exists. Swap the two after-cat sensors side to side, and see if the constant voltage follows the sensor to the other side (sensor problem) or if the problem stays on Bank 2 (cat or wiring problem).

You didn't get a code, because there are 3 possible codes for the B2S2 sensor, and it didn't meet the criteria for any of them to set:

P0157 - sets when voltage remains below 40 mV
P0158 - sets when voltage remains above 930 mV
P0160 - sets if voltage remains between 391-491 mV

A constant high voltage might mean the cat is not carrying out the "reduction" reaction, and not releasing O2 from the NOx.

 

I haven't done anything to the sensors yet; but, I scanned it again, the first bank, second sensor now stays (or atleast this is the first time I noticed it) between 0.2 and .3 or so volts.

So the driver's side is lean after the cat and the passenger side says its rich after the cat. With 76,xxx miles does that indicate the need for new cats?

I will probably end up switching the two sensors and see if the volt ratings stay with the sensor or with the cat they are attached to.

I looked at the "I/M Readiness" feature and it said the "Oxygen Sensor Monitor" was "inc"- as in incomplete or lacking enough information. I do not know why this is because it has not been turned off for a long time and I was testing it after driving for a little while.

Any input or comments would be appreciated.

 

I am about to swap the two sensors to see if the readings follow them instead of staying with the cats.

Any recommendations on an anti-seize which will not melt/burn up?

Thanks