Ford Explorer This long running SUV has stood tough against the barrage of new entries into the mid sized SUV market, and with a variety of engine sizes and trim lines, the Exploder offers something for everyone.

Codes P0171 & P0174

  #1  
Old 12-08-2006, 08:18 PM
Thread Starter
Join Date: Feb 2006
Posts: 8
Default Codes P0171 & P0174

I have a 1999 Explorer. I'm getting adaptive fuel too lean on bank 1 and bank 2. I changed the oxygen sensor on bank two. The code is erased but comes back in three days. I looked for a vacum leak but can't find one. Any known cause?
 
  #2  
Old 12-13-2006, 03:19 AM
Join Date: Dec 2006
Posts: 1
Default RE: Codes P0171 & P0174

I've been reading about the problems with mass airflow sensor causing these code problems. It gets dirty so you may want to clean the sensor. BE CAREFUL, it's a very delicate piece of equipment, try using electrical cleaner.
 
  #3  
Old 12-13-2006, 08:36 PM
Member
Join Date: Dec 2006
Posts: 47
Default RE: Codes P0171 & P0174

Did you replace all the oxygen sensors if its a 4.0L it will have 3 sensors just did that on mine. Also those codes will come up if you have a leak on the intake manifold especially if its plastic its quite common with those.
 
  #4  
Old 05-27-2016, 05:54 PM
Junior Member
Join Date: Feb 2014
Posts: 16
Default

What was stated already is very good. Another possible air leak are the manifold gaskets. Upper and lower. If you hear an air leak, but cannot locate it, consider that. When you do the lower manifold, you can look at the injectors in place. Just a thought. Good luck.
 
  #5  
Old 05-27-2016, 09:32 PM
Senior Member
Join Date: Dec 2011
Posts: 423
Default

since both banks are lean, you need to look at items that would effect both banks. bad maf is valid but rule out other items first.
-2 individual 02 bad at the same time is unlikely. the rear 02 are not used in fuel metering.
-look at the freeze frame data and see what rpms the dtc set at. Look at live data and read the fuel trim when in closed loop operation. Is is lean at idle, at 2500rpm or both?


fuel trim within +/- 10% is ok, 0% is ideal. over10% is a concern. the adaptive limit is 25%. +reading indicate a perceived lean condition and fuel is being added. - reading indicate a perceived rich condition and fuel is being cut.


if lean at idle but normal at 2500rpm it is not a vacuum leak.
if lean at all times, check fuel pressure at the fuel rail. If low, change the filter, if still low change the pump.
 
  #6  
Old 04-06-2019, 06:03 AM
Junior Member
Join Date: Apr 2019
Location: Keystone heights, Fl.
Posts: 2
Default

OTE=Shadow5;17937]I have a 1999 Explorer. I'm getting adaptive fuel too lean on bank 1 and bank 2. I changed the oxygen sensor on bank two. The code is erased but comes back in three days. I looked for a vacum leak but can't find one. Any known cause?[/QUOTE] I had same problem and found out that one of the 2 vacuum lines on the pressure regulator had a hole in it from wearing on the lower valve cover
 
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
makuloco2000
Ford Explorer
0
12-07-2014 01:08 PM
makuloco2000
Windstar/Aerostar
2
05-26-2014 09:53 PM
riemer
General Tech
1
07-24-2007 03:46 PM
haledonoem412
Ford Explorer
2
02-07-2007 10:41 AM
Bob Wells
Ford Crown Victoria
9
12-17-2006 11:24 PM


Thread Tools
Search this Thread
Quick Reply: Codes P0171 & P0174


Advertising
Featured Sponsors
Vendor Directory

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.