I've been having these codes for about 3 thousand miles now. Check most probable issues, MAF sensor was clean, checked for vacuum leaks with brake cleaner and nothing seems to be blowing my skirt up so to speak. Any ideas? 99 Ford Expy, no mods. 5.4l

 

check your DPFE sensor. if bad , ,replace with Ford part, not off brand

 

Did you check that rather problematic PCV rubber elbow at the rear of the intake for damage?

 

Checked the PCV elbow with no visible damage. Will check DPFE with workarounds i found and get back to ya. Thanks!

 

Ford P0171 & P0174 Lean Codes

hope this may help.

 

These were the codes I got. Please let me know as to your procedures to fixing this problem. A few pics to see which parts would really help me out as i am not too knowledgeable on this parts. 1997 ford exped.

 

I just replaced yesterday one of the PVC elbows on the 3 way splitter coming from the PVC valve. Totally collapse and leaking. What an amazing difference just in sound! I disconnected battery, codes 0171 and 0174 have disappeared and I am hoping they do not come back.

I started with two different auto shops telling me I needed to replace my O2 sensors, front and back of the CAT. That didn't sit well with me seeing how both banks were pining (0171 & 0174). I went home, seach the internet and found what else......this site. So, I am thankfull to the folks on this board, this is not the first time (probably not the last) I have found stuff on this site that has saved me a lot of money. So I figured I would join. The truck is getting older and things are starting to wear.

I was going to make an attempt at some photo's of the PVC elbow and the area it was (for the folks like me who LOVE pictures of the troubled aread) I replaced. I wanted to change the other two as well, but two auto shops did not have replacements. At any rate, 4.00 dollars and the truck is running fine.


I would be more than happy to send a photo via SMS text or email. I will try to post the picture of what I changed out to get rid of the 0171 & 0174 code. No joy on posting the picuture.

There was also another thread on this same subject..
https://www.ford-trucks.com/forums/5...-symptoms.html

Sparky

 

Ok i've checked the DPFE with a workaround I found on the net. It instructs to pull the two hoses from the bottom of the unit and take the vacuum line from the egr valve and place it on the "ref" port on the sensor. Then plug the two egr hoses that where going into the sensor and drive it to see if the cel came back on. The trick was to make the sensor and the pcm think that there was adequate egr pressure and not trigger a trouble code. Well this didn't work so i'm out of ideas. Any more suggestions???

 

Figured out what it was, three of the pcv connectors where bad so problem fixed thanks your all your help!!!

 

I checked the elbow and it was all torn at the 45. I replaced it and erased the check engine light. it went away and now it came back after 3 weeks. now the error code is p0442. but the lean codes did not come back.