It being a Pug mate the wiring could be at fault anywhere

I can just remember repairing loads those wires and funnily enough when i got mine 3 mth ago popped the cover off an it was nearly through the wire's, so i caught it just in time.

The high pressure pumps are known to go as well as ecu's best bets to get it on proper pug machine find out for sure whats causing it and take it from there you could end up pissing about forever and not find the fault and wasting money on parts you dont need.