and ve had it back to dealer this makes 4 times . first time light came on the def pump went out , drove it to 900 miles on trip an light came back on went to dealer he put egr valve in. i drove it 5 miles came back on ,i dont no what could be wrong it runs good.

 

Sounds like it's time to return to the dealership, ken1960. Once they give you a diagnosis, post here again so we'll know how things are progressing. Feel free to reach out via PM if you need additional assistance.

Crystal

 

took it back in today an he said it was throwing a code #401 and said it was something in E G R system said bring it back monday. he cut the light off but it came back on in 5miles, he said it would be ok to drive.

 

Dang emissions...

 

My 2014 6.7 with CEL on twice. Code said EGR. They replaced EGR valve. Ford dealer had my truck for 6 days. Have only driven about 15 miles since so not sure yet results.
Maybe not just an emissions thing -
1. AutoGuide.com "Top 10 LEAST RELIABLE cars and trucks", 6 of 10 are Ford/Lincoln products.
2. J.D. Power Most Reliable 2013 Trucks - I did not see any Ford trucks there.

 

What are the DTCs? Are they P0401 by itself, or is it P0401 accompanied by P2457 by any chance? In any event, if EGR valve replacement failed to resolve the issue, your EGR cooler assembly likely needs to be replaced. I have personally replaced a couple in for this particular concern, and it's the primary cooler that usually gets plugged up almost completely solid with caked on carbon, thus severely limiting or outright preventing EGR flow.

 

OK, Imagine a hospital. They measure your food intake (MAF sensor), and they measure everything that comes out (EBP sensor). With that, they can make a diagnosis. That code sets when the air intake does not measure up to what is expected coming out. Possible bad MAF/EBP sensor,aftermarket exhaust/intake system. Possible bad EGR valve. Restricted intake airflow. And like Mike said.

 

Furthermore, if a carbon caked primary EGR cooler passage is in fact the cause of the engine light coming on, the root cause will be poor fuel quality, prolonged or extended short trip/light load or "grocery getter" type usage.