Golf 6 1.6 TDI EGR OFF DPF ON - Problem

[apsol]

4 years ago I took my car to a garage to remap and they did stage 1 which is egr off but keep dpf. Sometime later I found out that you shouldn't disable the egr and keep the dpf because it needs it to do the regenerations, some even said that it will block the dpf very quickly.


Truth is the dpf is still working fine but I noticed that it takes much longer to finish the regen and more recently let's say 2 years, during the regen sometimes when I'm coasting and then accelerate I get turbo lag and then it wakes up and makes white smoke and cleans.


My question is why the egr is needed if it is 100% closed during the dpf regen ? Am I missing something ?


Today I was checking for exhaust smell from behind the engine I suspect the egr but I guess since the egr is disabled it doesn't show any error code.


Also the exhaust temperature sensors is playing funny, I arrived from work and let the car rest like 15 minutes, I go check the temperatures the first and 2nd sensor are showing 20ºc.


Could this be the problem ? No error codes also maybe because of egr off.


Please help.