Bought this downloader several months ago, runs fine on level 1 and 2, runs better on 3 for a while but then throws p0602 code. I can tell a difference in performance and not as much smoke after getting the code. Can clear it, run a while and same code again. Funny thing is i get better mileage (20.3 mpg) running on level 3 with the code than on the other levels. Any ideas?
fyi, lift pump and inj pump has been replaced during this time.

2002 2500, manual, 305's, 5" dual miter cuts.

 

don't know why it happens but mine had the same code with the hypertech but I didn't notice any difference in proformance

 

The Smarty people call that the Smarty code (p0602) because the ECM sees non-stock fueling. It is normal with a programmer and doesn't do anything. Do a search on "p0602".

 

Thanks for the information.