have a look here for the code meanings, http://www.pikit.co.uk/peugeotmt/psa%20eobd%20p%20codes.html P1291 Quote from site, For EW10D, SIRIUS81, check the operation of the high pressure fuel pump. This code seems to relate to failure. I have witnessed this fault, with the HP pump dropping pressure off, intermittently, and the regulator trying to increase pressure, as expected.