O2 sensor graphs

[dextergiii]

Hi,

Should the sensor in the picture somewhat mimic the pattern of the others? Not sure if the picture will come through but here's my try.

 

[2000StreetRod]

pre-cat or post-cat O2 sensor?

The pre-cat sensor outputs should cycle between .9 volts and .1 volts as the PCM cycles the short term fuel trims (STFTs). As they age .9 volts will drop to .8 and .1 volts will slightly increase. The left and right bank O2 sensors should look similar. The post-cat O2 sensors mainly monitor the efficiency of the cats. Their outputs look different than the pre-cat sensors but the left and right bank outputs should be similar.

What scan tool are you using?

 

[dextergiii]

Thanks for the explanation. I'm using an app called Torque and a Bluetooth OBD II module.