So my car has been running great since I got it and it was time to get it scanned for the emissions test to renew my registration. The scan goes well, the car passes, but less than ten miles after I get a CEL. I get home and read the code (41). I check all the wires going to the primary o2 and those are fine, so I take the sensor out and it sounds like the insides are broken (rattles when shaken lightly). I get a new sensor and reset the code but after a minute or two the light comes back on with the same code.

Now for the really strange part. MY brother took his 99 Civic CX to the same place and is having the EXACT same problem!

Could the testing facility's equipment have malfunctioned and shorted something out in our ECUs?

Does anyone have any suggestions on what else I could check on the cars before getting another ECU to swap out with mine?

Thanks for any help.