I've got the JWA and I have a constant 1693 too. I bought a code reader / eraser from Kragen auto parts and found that I have a 0336 too, which is a crankshaft sensor code, but..., the truck runs fine. I clear it and it comes back quickly. Even when I clear the codes, the 1693 remains...
I never had codes until I installed the JWA , go figure. I think it's just like Blue says, having a box just invites codes. Being aware and investigating them, along with keeping a good concept of your engines performance is all part of the deal of a 24 V second gen truck. If you think about it, it's a pretty easy engine to deal with in the grand scheme of things.
It is a companion code, so scan it when your check engine light goes on. A reader can be had for $50 so just get one. Deal with the real issues and enjoy the "beast" of an engine that you have. I mean really, where else can you get a 800 lb torque machine that pushes a 3 and 1/2 TON vehickle to 15 second quarter miles, and can carry a big ole cab-over camper and pull a big boat at the same time??

 

minw did this when the ground was bad on the wire tap side...good ground fixed it but had to get the codes erased. never came back

 

ok the light is off..but the code is still there..im not too worried..what code readers do you use..i dont want to spend too much..i also want it to erase them