Hi, I could use some help with a code p0406 on my 02 f150 4.6L 2wd. The last mechanic I took the truck to was just a parts replacer and not a mechanic. He replaced the EGR solenoid, the dpfe sensor and all O2 sensors with no luck.

The egr valve opens when a vac is applied. Dpfe sensor is receiving and sending out the correct voltage.

Another mechanic suggested maybe an intake manifold leak. He smoked it but couldnt find a leak. I have a Snap On MT 2500 scanner and I checked the STFT and it reads 4 to 13 at idle both banks and the LTFT reads 20 to 28 both banks at idle. At 2000 rpms the STFT reads 1 to -7 and LTFT is steady at 28.
Any suggestiouldprobably what else to check would be greatly appreciated, thanks.

 

http://www.obd-codes.com/p0406

Are you still getting the P0406 code thrown? Are you also getting the P0171/74 codes (I think they trip at 25% LTFT).

Did you replace the actual EGR valve?

 

Yes still the 0406. I was getting 0174 but I think it cleared after the mechanic replaced O2 sensors. Still got the origional EGR valve.

 

i have a f150 2001 4.6 and my EGR code(p0401) kept coming up final i took off the throttle body and the intake cleaned it where the EGR vale hooks on you and you should be good you will need some gaskets and b12 cleaner should take about 3hr to finish. the code should goo away it did with mine good luck let me know if i can help further