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.
thank you i will look into that
I would start by checking codes and data. It sounds like it could be a vacuum leak or faulty IAC valve.
I have the same problem. i replaced the plenum gaskets about a year ago and it went off for like 6 mths. my maf was then cleaned and it went off for like a week. now just recently when i sit still with the engine idling for a bit it will stall on me after the rpm goes up and down a bit. any advice?? thank you so much for your help!
The post I did is not a magic fix for all possible causes of P0171 and P0174. It is just one of many things that need to be looked at. Your O2 sensors and DPFE sensor may have had issues by themselves, but they would not cause the two listed codes without having more codes stored in the system also. My advise at this point would be to tell you to read the last two paragraphs of the repair post that I did along with the last comment I made. I think you may find your answers there.
I have this same problem but can’t get it fixed. I have already spent $350.00 taking it to the mechanic three times and it’s still not fixed. He cleaned the mass air flow sensor and the light stayed off for about a couple weeks then it came right back on again and has been on ever since. Well, we spent mroe money as we changed out the o2 sensor and the DPFE/EGR sensor and the light still came back on again. I’m still getting the P10171 and P10174 bank 1 and bank 2 lean codes. I’ve had three diagnostics done on it and it’s still hicupping. it acts like it’s coughing at times. I am just about to lose my mind over this issue. Is it possibly just a bad MAF sensor that needs to be replaced? I’ve even tried GumOut in the tank to clean the fuel system. I’m a girl and at this point, I decided that I have to obviously do this myself cause noone else can seem to figure out the problem. I am so discouraged now because I have been battling this for about a year now and it’s very frustrating. Any advice would be greatly appreciated.