Originally got a P0405 code replaced the DPFE sensor, after replacement I got P0401 code I then replaced the EGR valve. now I'm getting a P0405 again. All hoses, connections etc are in good condition. The error reads "Exhaust Gas Reciculation Sensor A is low" I am getting no other error codes to indicate something else upstream is causing the problem. Any help appreciated.

 

Vehicle details, please.

 

Im also havibg a similar problem with my 04 f150 4.6l...

Ive cleaned TB, replaced the EGR module (dpfe included) and searched religiously for vacuum leaks... nothing has worked.