non start fault code 01314 bkd engine code

hi all

i have a octavia with the bkd pd engine fitted 2004 year model

the problem i am getting is intermittently when going to start the engine, the eng man and glow plug lights do not come on and it wont start . i have checked the dtcs with vag com and it allways comes back with fault code 01314 no comms to engine controller stored in the instrument panel/abs ecu/can gateway/steering assist/central elecs/ i have changed the main eng controller relay but still the same . any ideas would be gratefully recieved

thanks simon