How do you check a one wire O2 sensor? The book says "Connect and analog voltmeter between the oxygen sensor electrical connector and ground." Another place in the book says " Connect a voltmeter between the sensor side terminal and ground." According to the book I am looking for voltage, but how do I get voltage from an oxygen sensor with one wire? I did get .2 volts when reading the connector on the car side, but on the exhaust side, nothing. I know this is probably a stupid question, but I am really confused.

Thanks,
Mark

 

you need digital not analog, connect lead to the single wire and ground the other, you then read the voltage it puts out, an O2 senser is a voltage generator. check your book for the correct voltage value, i think it's something like .8 volt

 

O.K., thanks for the help! I didn't know that it made its own voltage and I guess that is how I got confused. The book says it will vary from 0.0-0.8, I read 0.0 and it didn't vary. The car was running VERY rich for a couple of months, I fixed that problem (I think) so would no voltage at all mean that the oxygen sensor is bad now? The inside of the tailpipe is VERY nasty with black soot.

THANKS!
Mark