[MMGT1]

Check the EGR tube to begin with. The 401 is insufficient flow DTC. If the tube is cracked it will throw the code your getting. Ive seen quite a few now that the metal tube has corroded or cracked through. If no crack, check wiring to the EGR, maybe a corroded/bad connection happening there on you
And that white stuff your seeing happens when a vehicle is not brought to full temp. Not getting the oil up to temp will allow moisture to stay in the system and that is the milky brown sludge that will result. Try to get it out and up to full temp at least a couple times a week if the car is subjected to short trips too often. A good half hour to 45 mins on the highway will do wonders to keep that issue at bay