HO2 sensor issues.....
 

I have had an 02 sensor code on my truck for a while now, finally got around to replacing it. the code went away but the OBDII reader at advance still shows 0 volts for all o2 sensors. I am getting 12 volts on 2 wires at the plug. Has anybody else had a similar issue?

Welcome to the forum

I assume a Ranger
Year and engine size would be helpful

O2 sensors all have Heaters, thats the 12volts.
Computer is the Ground for each O2 heater, so it can monitor that heater is working
There will be a Fuse, usually 15amp, that powers all the O2 heaters

The O2's sensor part generates it's own voltage, .1 to .9 volts, that is done with a chemical reaction with Oxygen, no truck power involved

OBD reader can select either.

Sensor voltage only shows up after engine is warmed up and running


So which voltage is at 0 ?

Re:HO2 issues
 

Sorry bout that, thought it would show up on the side because it had me put all that in when I made my account. My truck is a 98 ranger 2x4 with a 3.0. I checked fuse #13, it's fine. In the scanner, it is showing that it is in closed loop, and it is still showing 0.00 volts for all 3 o2 sensor readings. is there a way that I can check the o2 sensor outputs with a multimeter?

I would say it is a system/computer issue if all 3 show that.

If you have access to scanner/reader then reset computer

You can read O2 voltage with engine warmed up and running, lowest setting for DC volts on meter
Orange wire is the Ground for all the sensor, not heaters just sensor ground
It goes to pin 91 on computer

#1 sensor is grey/blue wire pin 60
#2 is red/black wire pin 87
#3 is red/green pin 35

Problem in the computer would mean you would still read 0 volts because of short inside computer
So you may need to cut one of the wires, 60, 87, 35, and then read its voltage to determine if computer is the issue