I had a code come up on my 2005 CTD. The engine had a misfire as i was pulling out of the drive way & then the check engine light came on. I took it to Napa to get the code, came up P0340 so I replaced the camshaft position senor,I had the battery disconnected for 5 hours as I did the work & took a long lunch. put things back together truck runs great & the light went off. Can someone tell me if the code got cleared or do I need a scanner to clear things?

 

Usually three key cycles and IF there are no more code issues the ECM will clear itself.

 

Everyone should own an OBDII scanner.
A basic scanner goes for less than US$50. This will work on all vehicles since 1996.

Disconnecting the batteries will not usually clear codes. You want the ECM to save the codes even if it loses power.