This 2003 Ford Windstar came in with the service engine soon light on. Checking code revealed codes P0171 and P0174, banks 1 and 2 lean. I checked for vacuum leaks and none were found so I moved on to the Mass Air Flow sensor. It is common for them to get dirty and cause these fault codes. The MAF sensor is located inside the air filter housing so it had to be removed. I loosened both hose clamps and pulled the rubber boot from the throttle body and then from the air filter housing. Then I unlocked the spring clamp that holds the two halves together.
The crankcase ventilation tube also had to be removed from the rubber hose and more importantly it has to be put back in place during assembly. You can see it just to the left of the master cylinder.
After unhooking the wiring harness connector I took the housing to the bench for dis assembly. There are several locks that have to be released. I used a common screwdriver blade to pry them inward while pushing the sensor out from the other end.
There is also another wiring subharness that has to be removed. It is kind of a pain but I take my time so as to not cause any damage. Once the two halves were separated I removed the sensor from the housing using and tamper resistant torx bit socket.
This is were the actual sensor elements are located and in most cases you will find a build up or film on the element. I use a pick as shown or a small screw driver and very lightly rub the film off. Sometimes if it is heavy it will lift off in one try but most of the time it takes a little while of very light rubbing to remove the film. Some people use cleaners but I prefer to manually rub it off so as not to cause and damage to the sensitive parts. Many cleaners will damage the plastics.
Just several different pictures of the same sensor. There are two elements inside and the most problematic one is the one further inside that you cannot see.
This is just one of the possible causes. There are many and one of my readers left a link to a repair site that has more answers on this problem.
Ford has a TSB out on this for 1999 to 2003 Windstar. if you want to do it yourself, you need to go to your local parts store or dealership and ask for a “Valve cover repair kit”. This site link gives step by step instructions for the fix.
Hi Kan,
I know there were tsb’s or technical service bulletins issued for the problem related to the front valve cover, the intake bolts and seals. However you would need to contact your dealership about any recalls.
Are there any recalls covering 2002 Ford Windstar SEL indicating PO171 codes?
I have already replaced the wires, plugs, distributor, and air filter.
The code went off for a few months and has now returned.
I have only 83k miles on this vehicle. I feel this is a well known problem, especially
the possibility of needing to change the valve covers so I think it should have a recall.
Thanks,
Kan
After over two hours of searching the net concerning this problem and reading mounds of brainless garbage, I came upon this site. This guy knows what he is talking about and articulates it very well. It takes a magnifying glass, small improvised scraper and bright sunlight to see and clean the elemnets but it is effective and will save you big bucks like it did me. I have the 6 pin Ford MAF. Ohm meter testing showed conductivity between the center two pins (only). It apparently indicates a healthy MAF except for the accumulated coating that he describes. Carefully remove that and bingo you are on your way. My hat is off to this guy.
Thank you for the advise on My 2003Ford Windstar.
At this point I will have to advise you get the assistance of a professional mechanic. To locate a vacuum leak there are two basic methods: add an external fuel source to the outside of the intake area and either listen for rpm changes or look for changes in engine data with a scan tool (this can be quite dangerous), the other is to use a smoke generator attached to an intake port to a none running engine and look for smoke escaping. Fuel volume and pressure will need to be checked with a fuel gauge with a tee port. The MAF sensor will have to be checked with a scan tool, multimeter and or scope.