4727 code

[JimT]

did you try logging in to Cummins Quickserve (free account for owners with up to 5 ESN's), look up the code and follow the associated troubleshooting instructions? Off the top of my head, for an over pressure code I think the possibilities are the fuel rail pressure relief valve or the fuel pump (actually I want to say the bypass valve in the pump head, but I could have the name wrong). My money would be on the pump head, but thats just a guess from a guy on the internet reading a few sentences.

Like I started out saying, look up the fault and troubleshooting information and go through the steps laid out to properly test and diagnose the issue.