How to test oxygen sensors that were removed from vehicle


I pulled off oxygen sensors from my car after it was totaled in a flood. They were installed, brand new, one month prior to the flood. Is there a way to test them to see if they still work without installing them on a car? The car was towed away. Thanks.


It can be tough to do. You could perform a resistance check through the heater circuit, IF the O2s have this. You cannot perform a resistance check for continuity through the O2 output circuit as the O2 can be damaged even with a digital VOM.

If you own, or have access to, an older vehicle with no converter it’s possible to place one in the tip of a tailpipe with a VOM connected to the output circuit. It may work well enough to get the VOM needle twitching on a 0 to 1 volt scale but it sounds like a lot of trouble.


Thanks for your reply. What do you think are the probabilities of them still working after being submerged under water for several hours?


There’s no way of knowing for sure, but a wild guess might say they’re still good if the vehicle was not running when it flooded and it was a simple matter of rising water.

Leave them out in the sun for a few days. If by some chance they absorbed water through a microscopic pore it’s possible that if there is any water in there it will also be pulled out by the heat from the sunlight.
JMHO anyway, and I could be dead wrong.


If they weren’t cracked, there wasn’t any water in them. They get wet all the time. You can dry electronic parts by leaving them in the sun for a couple hours anyway. They’re nearly indestructable and don’t take up much room in storage. Keep them or not; having them won’t make you rich and throwing them away won’t make you poor.


Although I’m not 100% certain on this, I believe there is no way to test off-car O2 sensors without special laboratory instrumentation. My guess is that they are perfectly OK. A soaking ought not to affect them at all.


They’ll be OK unless the car was soaked in salt water. If the water was salt, throw them away. LEE


I once read an article on the net that explained how to test the sensor using a propane torch. I’ll try to post back if I can find it.



Thanks for all the replies. It was a fresh water flood. I kind of thought that they should be ok, but I would like to try to sell them and wanted to be able to make sure they work before selling them. I think I might actually try the propane method - thanks for the link.