how to fix error code po401 and code po171 on 1999 f150 4.6 motor

Asked by Aug 23, 2017 at 05:03 PM about the 1999 Ford F-150 XL Extended Cab SB

Question type: Maintenance & Repair

3 Answers

23,930

PO171 is lean code for bank 1. PO401 indicates the computer has determined Exhaust Gas re-circulation is insufficient. Check the net for Ford vehicles which experience both codes as once. Saw a couple of videos which may be of help.

2 people found this helpful.
10

Check for clogged ports on the EGR valve. The passageways get carbon-like deposits that block the EGR valve.

1 people found this helpful.

thanks,this helps

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