Put it back wherever it came from.

 

Looks like a front wheel speed sensor

 

Spoken as our departed Johnny Langton would have offered!

 

It's definitely one of the front ABS sensors.

Sigh...

 

I had a bad front ABS sensor on the front of my 04'. It did not affect anything that I noticed until braking.(under 10mph) The ABS would kick in a pull the steering pretty hard to the one side. Something I fixed rather quickly, doesn't hurt to have a spare.

 

 

Same thing the Chevys did - the knuckle would corrode under the ABS sensor, pushing it away from the tone ring and causing a low-voltage condition at slow speeds. Scared the bejeezus out of my brother-in-law. The .2-.3 volts check is a great indicator of this. In your case, who knows

 

In my case the damn thing was stuck fast in the bearing, had to remove it to grease my wheel bearings. I must have cracked a wire in the sensor even though the sensor looked fine. I pulled one apart later and saw how thin the wires were at the tip.