egr vauxhall astra 2.0 dti j?

A forced regeneration can only be done if you have the correct computer like Tech 2,your ECU in the motor will decide when it needs done through sensors either side of your DPF measuring the difference in pressures, it needs careful consideration nowadays whether to buy a motor with a DPF if you are town driving all the time.

cdc
December 2016

http://www.hypermiler.co.uk/egr-valve/the-exhaust-gas-recirculation-valve-egr-faq

https://www.theaa.com/driving-advice/fuels-environment/diesel-particulate-filters

Good Luck...
December 2016