How To Diagnose Oxygen Sensors

[rwdbmwm3]

Does anyone know how to diagnose oxygen sensors?...

(Tool Owned: Genisys Scanner)



or any common tests like

-Check resistance of sensor?
-Check continuity of sensors?
-How is the sensor suppose to respond on scanner (Graph)
-(minimum voltage somewhere around .10 to .15 ?)
-(maximum voltage somewhere around .85 to .90 ?)
-(average voltage somewhere around .45?)
-how is it physically suppose to react?
-Can i do anything to create a reaction... snap the throttle and the oxygen sensor should go to maximum, then drop to minimum, then even out

(I will add if i think of anything else, anyone that has any input on this would be greatly appreciated, maybe we can create some sort of a "STICKY" for O2 Sensor Diagnosis)

[shorod]

There are a few good articles on how the sensors should react. Also, different composition oxygen sensors do react slightly differently. The standard O2 sensor will function like you describe though. These probably account for more than 90% of those on the US roads.

Also, the forward sensors (Sensor 1) should react differently from the post-converter sensors (Sensor 2).

The forward sensors should switch between lean and rich a few times per second, whereas the post converter sensors should switch very slowly if at all.

One site that has a reasonably good, generic description is AA1 Car. A quick Google will likely result in many more. I have yet to figure out what the sample rate of the Genisys is, but it is definitely slower than a typical oscilloscope. Therefore, the datastream graph of the O2 sensor voltages may look slightly different than those shown at the above link.

-Rod