Fuel rail pressure sensor

Hi. I am new to the forum and this is my first post, so I apologise if I get anything wrong. I have an '04 Scenic 1.9dci that I had to get recovered the other day. Whilst driving the STOP and service lights came on and Injection failure message came up on the dash. The car now wont start. The guy that recovered it plugged in his diagnostic thing and it came up P0190 fuel rail pressure sensor A circuit. Can anyone help as to what this might be and if I change it would the fault code need to be reset before the car will start? Thanks for any help anyone can give