Finding diesel fuel on the go?

[Diesel Guy]

I was returning from Maine last evening.....6 degrees F outside......I was pushing to see how far I could go on a tank of fuel, and got a little too close from my passenger's comfort. I found that the best way to find Diesel stations is to have the Nav on a route....and chose the find stations along route option. This will give you a look ahead to find a station.

I ignored my '60 miles to empty message' and went by a couple of stations, then with about 15 miles to empty.......I had 1 ahead at 12 miles.......when we got of the interstate, I was at "0", and nursed it along for 3 miles to the Hess station. I put 22.372 gallons into my 22 gallon tank............whew.....

When I restarted at the pump, the check engine light came on.......I think she was mad at me..........It stayed on another 40 miles, and when I hooked up my OBD tool this am, I get a P0420 code............which is an 02 sensor/catalyst code............a code that I cannot clear.............So I'm wondering if it's just a coincidence, or is it because of the seriously cold temps ?