Well, first your second question, OBD II codes are industry standard with places for each manufacturer to customize. Just Google OBD II [the code] and then the make and model. You'll find the description and lots of people's experiences.
I like the silicone jelly used on pool O-rings for lubricating rubber gaskets. While not totally weatherproof, it is waterproof. Apply sparingly and reapply as needed.
TT 2015 19RD "TheJayco"
TV 2003 F-350 "Montblanc" - Housebroken chore truck
Sitting in The Cheap Seats.
And proud of it!