Daryl, why can't you use an ohm meter on an oxygen sensor. Does it ruin the meter or the oxygen sensor.

 

Yes, it does (the sensor - the meter will be fine). The sensor circuit (not the heater circuit) is not designed to have current applied to it, even the small amount from an ohm meter. It is a device that turns heat and gas into electricity in a very specific way, and only puts out around .9 volt at maximum. Moderate voltages/currents applied to it will destroy it or at least shorten its life - it is designed to produce voltage, not be fed voltage.

More importantly, there is no reason to check it with an ohm meter across the sensor terminals. Even f it doesn't destroy it, it's just not going to tell you anything.

You can test it with a 100 ohm resistor and a meter that can read on a 1 volt scale (or better yet an oscilloscope) either while in the truck or by heating the tip of it with something like MAPP gas on the bench.

 

Thanks for the info Daryl. I didn't know much about oxygen sensors.