Engine management and esp/asr system fault

Had this problem a few weeks now first time Engine management light came on along with ESP/ASR System fault it was taken in to be repaired i was told DPF Fluid was empty also had AD Blue topped .
Then driving from work one day it seemed to lose acceleration so came to a stop engine was still running , engine management and ESP code came up .so i called our machanic he advised re starting , that worked and i was able to drive home still had engine man light on . following day we needed to move the van for access and it would start but soon as acceleration it cut out , machanic came to collect turned off fault lights checked everything and said it was the Ad blue nox sensor returned following day .
now ESP/ASR came up again van starts then chuggs and cuts out slitght smoke on last attempt