P4401 error code check engine light is on - 2001 Ford Taurus

https://www.engine-codes.com/p0171_bmw.html this link has all info needed to assist you

Where I live most auto parts stores will check and give you the error code which set off the check engine light. That will tell you the basic system which is setting it off. You can search of what other have done to repair for the error code.
https://www.engine-light-help.com/subaru-check-engine-light.html
https://www.youtube.com/watch?v=DhDzA-6dFm4
https://www.youcanic.com/guide/subaru-check-engine-light-problems
https://www.tricitysubaru.com/check-engine-light-on-.htm

118, replace the coolant sensor. 440 is a small leak for EVAP. Could be as simple as replace the gas cap. 101 could be the MAF sensor or wiring to it. 300 is random misfire, needs to be on a scanner, Could be related to MAF sensor. 4401 is not a valid engine code.

Hey are you sure on that engine code number friend.. I cannot find that at all in the code book i can find.
here is one of the multiple links i found and seems none go over p3999

Check engine light comes on and off, these are indication that there is some error code stored in your vehicles ECM. The engine module computer needs to be scanned. These will give the code and as per the error code the further problem can be detected and confirmed. The engine light indicator blinks or remains steady on dash when engine computer noticed any problem with any engine electrically operated components.

For more help, I suggest you to refer the help links provided below. These will let you know more about which areas to look, check, when there is engine light coming up on dash panel.

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Click the link below: -------

CHECK ENGINE LIGHT

http://alltypesofpartsreplacing.blogspot.com/2012/12/check-engine-lightengine-warning-light.html

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Check Engine Light Reset Procedure?
http://whoisbyme.blogspot.in/2012/06/check-engine-light-reset-procedure.html
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These will help.
Thanks.

As per your problem,the check engine light comes on due to technical problems in your car.In this case i suggest you to click the link below :----Check Engine Light On car? http://schematicsdiagram.blogspot.com/2011/06/check-engine-light-on-car.html
------------Basically the computer needs to be scanned to retrieve the error codes stored in ECM.In this issue,i suggest you to click this link:----How to Read Codes from Check Engine Light? http://schematicsdiagram.blogspot.com/2011/12/how-to-read-codes-from-check-engine.html----------After scan procedure you will get P4 digit error codes.If suppose you get this error codes,then click the link below,to know more about error codes:----

Check engine light with codes P2195 and P2197?http://howtobyme.blogspot.in/2012/01/check-engine-light-with-codes-p2195-and.html
---------------There are many other reasons to for check engine light coming ON,i suggest you to click this link below and go through its troubleshooting procedure:---------Car jerks while going uphill and Check engine light is ON?http://schematicsdiagram.blogspot.com/2011/12/car-jerks-while-going-uphill-and-check.html
--------One more reason is as follows :----After getting car washed, check engine light is ON and key less entry not working, tried reprogramming. Also car shows fuel pressure?

http://schematicsdiagram.blogspot.com/2011/12/after-getting-car-washedcheck-engine.html

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After replacing throttle body the Check engine light starts blinking?http://technoanswers.blogspot.com/2012/01/after-replacing-throttle-body-check.html

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This will help.Thanks.

As per your problem,the check engine light comes on due to technical problems in your car.In this case i suggest you to click the link below :----Check Engine Light On car? http://schematicsdiagram.blogspot.com/2011/06/check-engine-light-on-car.html
------------Basically the computer needs to be scanned to retrieve the error codes stored in ECM.In this issue,i suggest you to click this link:----How to Read Codes from Check Engine Light? http://schematicsdiagram.blogspot.com/2011/12/how-to-read-codes-from-check-engine.html----------After scan procedure you will get P4 digit error codes.If suppose you get this error codes,then click the link below,to know more about error codes:----

Check engine light with codes P2195 and P2197? http://howtobyme.blogspot.in/2012/01/check-engine-light-with-codes-p2195-and.html
---------------There are many other reasons to for check engine light coming ON,i suggest you to click this link below and go through its troubleshooting procedure:---------Car jerks while going uphill and Check engine light is ON? http://schematicsdiagram.blogspot.com/2011/12/car-jerks-while-going-uphill-and-check.html
--------One more reason is as follows :----After getting car washed, check engine light is ON and key less entry not working, tried reprogramming. Also car shows fuel pressure?

http://schematicsdiagram.blogspot.com/2011/12/after-getting-car-washedcheck-engine.html

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After replacing throttle body the Check engine light starts blinking? http://technoanswers.blogspot.com/2012/01/after-replacing-throttle-body-check.html

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This details will help you.Thanks.

Please see my tip at http://www.fixya.com/cars/r5932051-check_engine_light_check. These are generic instructions. If you get stuck or need specific instructions for your car, please get back to me with model, year and engine info.

The check engine light comes ON,when there is error code stored in the car computer. to get car scanned at diagnosis center to get error codes, At diagnosis center you will receive the error code.As per the error code it will detect the exact faulty part in the car due to which the problem is occurring.For more help :--- at www.autozone.com its absolutely free to get car scanned.
Thanks. Keep updated for any more query. You can rate this solution and show your appreciation.

Error code will have to be cleared. The way that cars know when to turn on the check engine light is that there is a recurring error for "x" miles or time, as long as that error exists in it's memory most cars will continue displaying the check engine light.