I have bought 2011 2.2 diesel which needed engine changing. After I got it sorted I took the car to halfords for dpf flush as the light was on and I also needed mot done. They cleared the light and all good but I have done 60 miles and the light came back on. I only have a cheap obd reader and it's not showing any codes or faults on torque (lite)

 

Cheap scan tools don't/can't read all the DTCs/fault codes.