2017 2.0TDI 140kW bad EGR?

Hello everybody,

today after oil change + fuel filter/air filter I grabbed my VCDS and tried to reset service oil + set new interval of changing oil from 30 000km to 10 000km.

After this, I was courious if anything new appeared in errors, my last check up was last year in november.

So I went to read all faults and all was clear ,but in engine I had two faults. Before I read this faults with VCDS, I didnt have any check engine on my instruments, but immediately after reading faults engine check appeared.

P046C00 and P040500

One si from 2024 and without engine check light till now.

But second one appeared right after I scan it - 144 000km 

Car is running normally, without any issues.

So I deleted it, drive for another 10 kilometers, stopped, check VCDS again and it was clean.

Now Im courious, if this is some random abnormaly or should I expect the worst? 

I dont have genuine VCDS, but so far it worked very well and read everything right.  

Could this be also fault reading? 

Why check engine appeared after I read the fault codes and no before reading?

Thank you very much and sorry for my bad english also.