Hey i have a 1406 code coming up for my truck which my reader tells me is a differential pressure feedback circuit downstream hose or something to that effect. I am not educated on what this is or does or how to fix it. Any help or suggestions I would greatly appreciate it... Oh i have a 2002 f150 fx4 5.4l
thank you

 

this means that your sensor is out or is plugged. This could also be an EGR problem. i would unplug the EGR and make sure its not gooked up... the sensor your looking for should be on the driver side right after your header's on the downpipe. if you need more help let me know