check engine light-OBD II tester says O2 sensor WTF!

[FASTSPOOLINGST]

I recently did a turbo, mani and O2 housing swap and after I put the components on my downpipe would not bolt up to the Evo III O2, so i drove it to the muffler shop unbolted. I got a check engine light so i assumed it was the O2 sensor in the exhaust not getting a reading due to it being disconnected. I then had my pipe welded to the new flange and bolted it up. I then took my car to auto zone and had them use their OBD II tester on it and sure nuff it said O2 sensor. I then had them erase the error code. I then took off driving down the road and it popped back on again. I have the same O2's that I had when i took everything off, i did not pinch any wires or anything so i don't know what the f is going on. Somebody hook a brotha up

Only thing i can think of is when i was spraying some Gunk on it, some got in the connector plug????????

 

[1gCTgSx]

Take a voltmeter and go from the signal wire of the 02 sensor to a ground. You should get somewhere around .450-.500 while your motor idles. If you get no signal in any of the wires, go pick up a new 02 sensor, if you do get a signal from one of the wires, something besides the 02 is broken and you might as well bring it to a mechanic.