Just had converters installed on my 99 5.4 and now i am getting p1406 code. Any idea? Could it be something that happened when converters were installed or due to 138,000 miles ? Truck is running great plenty of power .

 

Look at your EGR and the DPFE to see what hose has come off.

 

Many thanks torkum Iwill check when i wake up. Was replaing #6 COP yesterday also, i'll bet i knocked a line off.

 

The line came off of the DPFE. Reinstalled and no more codes. Thanks again.