P1DF3

[Bullet Bob]

6 year old battery died. Replaced battery. Upon first start got engine light and P1DF3 code. On fourth restart, engine light went away. Computer decided to act right and corrected itself.

 

[kapinallinen2]

Transmission Control Module (TCM) (8HP75) - ECU Not Initialized.​

Most likely cleared the DTC because of the number of key cycles.
Batteries going bad play havoc with these trucks.

 

[HSKR R/T]

6 year old battery died. Replaced battery. Upon first start got engine light and P1DF3 code. On fourth restart, engine light went away. Computer decided to act right and corrected itself.

Code is from battery dying and subsequent replacement. It takes a little while for all systems to come back online. The light going off after a few drive cycles tells.you there isn't a problem