Ck engine lite on for 150+ miles. Just got somewhere we were able to have an Auot parts store ck the code which is P0401 (EGR) Exhaust gas recirculation, insufficient detection.

This AM the ck engine lite is off. My question is what harm is caused by running the trk with that code if it comes back on as we are on a 2500 - 3000 mile round trip.

 

It's a very common issue and it will most likely come back on... IMHO there is no harm in leaving the light on (and doing nothing about it) for the short term 2-3,000 miles. In the longterm, you probably want to do something about it. I believe Ford has a cleaning procedure which is quite labor intensive to increase airflow or you could do an EGR delete... or a piece of black tape on your dash