Good day everyone GarageKing here and today I'm gonna show you how to check an
oxygen sensor this one has four leads that means that
it's heated some of them have three leads some of the older ones have two
leads and some of the very very old ones only have one lead where they actually
use the sensor body itself as a ground so if we think to ourselves this one's
got four leads to leads are used for the heater and two leads are used for the
oxygen sensor itself to produce the voltage so if we connect an ohm meter to
the two leads which are usually the white leads then we should have a
resistance and that'll tell us if our heating element is good so first we're
going to check the heating element for resistance so normally it's the two
white wires if it's not the two white wires on yours you can just keep trying
different combinations until you get it you're not going to damage anything by
doing that so two white wires let's plug our little connectors on like so and
then we're gonna hook them up to our multimeter over here so let's hook it up
to our multimeter put on ohms and let's see what we got here Ohm's that would be
this one maybe I need a new battery soon and there's our ohms so 10.9
ohms that is okay we should get around the 10 ohm mark so we know the heating
element is okay so let's turn it to voltage and let's hook up the other two
and let's apply some heat and see what happens there we go so now we've applied
or we've hooked up the black and the gray one and now we're on the millivolt
we're on the Volt scale and let's see what type of voltage we get out of the
o2 sensor when we heat it now just for this test I'm just using a butane torch
I might take a bit to get this thing heated up but once it heats up we should
see some bolts coming out there and all oxygen sensors produced between 0 and 1
volt so we should get somewhere around there let's check it out
and what it actually does is it measures the amount of oxygen that's left which
depending on like with this flame there's not much oxygen left because the
flames earning it all and you can see it's going up it's still on the
millivolt scale let's get a little more heat maybe to the backside here and
there we go we're at point three of a volt point two of the volts we're back
to the millivolt scale point four of a volt and there you go so we're roughly
around half a volt so we know this thing works points 5 volt point 6 volt so it's
working so why did I change this well it did have a check engine light and the
computer kept saying this is faulty now there's a number of things what can
happen we know here it's working but what we don't know if it's if it's
calibrated right and if it's not calibrated right that's why you can get
a check engine like so a lot of times they don't heat up fast enough maybe
because they're dirty so then you'll throw a check engine light if it doesn't
heat up fast enough the other thing is if it is dirty there it may not be
reading the proper amount that the ECM is calibrated for so there could be a
number of things so we know this one actually works it did have a check
engine light so I did replace it but it's probably not calibrated right
because it's probably all dirty now what I could do is I could try to put it in
some gasoline or some type of solvent clean it put it back in the vehicle and
see if it works but in this case it was just faster just to replace it and the
check engine light never came back on so I can conclude that this does work but
it's out of spec so if ever you pull your oxygen sensor this is an easy way
to test it but if your check engine lights on it's I would have to guess
that it's probably just dirty and you got to clean and now I don't know if
it's worth your time to clean it or not you can see what you want to do if you
want to clean it try it maybe that's what I should do
one of these other check engine lights that I get on if it's an oxygen sensor
maybe I should take it out do this clean it put it back in and see if it actually
works so with this one I actually just replaced it so now we're just checking
the old one so we know it does function the way it's supposed to function but
it's probably just out of calibration because it's dirty so anyway that's it
for my video today nice and quick folks hopefully you've
enjoyed my video I'd appreciate if you would subscribe means a lot to me trying
to grow my channel that's it garage King over and out I'll see you on the next
one