My car had an evap code that was diagnosed to be a crack in the evap vapor canister; this was done with a smoke test. The code was P1456. I replaced the canister and have not seen any codes come back. As part of clearing this code, the readiness monitors on the car were cleared and now the issue is that the IM monitors have not all registered. The O2 Sensor is still showing as incomplete even after days of driving and going through the drive cycle procedure.

Is it possible that any of the oxygen sensors is not performing correctly and this is causing the monitor not to register? I recorded a short trip (from cold start) of the O2 sensors, but not sure how to read the graph exactly to identify the faulty one.

My understanding is that the O2 sensors should vary between .2 to .9 V depending on the amount of oxygen present in the exhaust. In the first set of graphs we see that the sensors are all within that range and they never touch 0 or 1 v.

In the second set of graphs, we see that all sensors at some point touch 0V. If they were all bad, I would anticipate that I would see a MIL on the dash, but I don't.

If anyone could help, it would be greatly appreciated.



Graph 1 - Cold start and short trip


Graph 2 - Drive from gas station to expressway and back

 

they maybe going bad due to age. Wear and tear

 

One if the four sensors was replaced 2 years ago. Don't remember off hand which it was, but I expected to be able to tell through the graphs, and I can't. All seem to perform the same.


EDIT: Another thing to note was that the engine is in a closed loop almost always, unless I accelerate to above 50 mph or so and then let go of the gas for a few seconds.