My "Check Engine Light" came on Friday and i had a buddy hook up his OBII reader. The code came back as PO401. After looking around it seems like its an easy fix from what people say, but i have had this clicking noise comming from under my hood for a little while now too. My mechanic friend says it sound like an exhaust leak. I have been un able to find anything myself yet that seems to be leaking exhaust. I can't help but wonder if these two things could be related.
I have a 2001 3.8L vert with stock everything. I also just changed the spark plugs and wires last week at about 62,000 miles.Anyone know if these two things could be related?

 

I'm not sure exactly what years but 99-04 3.8l Stangs are notorious for exaust leaks in the stock headers. My 01 has the problem. Sounds like valves tapping..

 

Check the passenger side header for any cracks in the welds. Never heard of one throwing a code though.

 

seperate problems fo sho

 

the code is for the egr, its showing insuficent flow. maybe the connection from the header to the egr pipe broke some how and thats why its ticking and throwing a code. i would clean out the egr tube and valve and everything then disconnect the neg battery cable and reconnect then start it up again and take it for a drive. if it doesnt come back on then thats awesome if it does then you might need a new egr valve or dfpe..or whatever its called sensor..the silver box that connects to the rubber egr tubes.

 

+1 Fords in general are notorious for a DPFE sensor going out. This sensor will either throw P0401 or P0402 (excess flow) depending on whether it's stuck closed or open. The sensor is located on the passenger side, above and just behind the A/C compressor. It will have an electrical connector and two vacuum lines going to it. It will look like this more-or-less.

http://www.moddedmustangs.com/forums/files/dpfe_215.gif

If you have no leaks, I would guess this is your problem as it controls the opening and closing of the EGRvalve. I would say you're stuck closed since it's giving an 'Insufficient' code.

 

Thanks for the info guys.. I'm gonna go ahead and replace the dpfe sensor tomarrow and take a look around the headers for an exhaust leak. Hopefully the dpfe will fix the check engine light, but i do need to get rid of that exhaust leak its SOOO annoying.

 

I have one concern, is this that DPFE sensor i need? http://www.napaautoparts.com/masterp...osition+Sensor
My Hanes book says i have two screws to take off but this one does not look like it has any screws to unscrew. If its right i'm ok with that but i dont want to throw 30$ away for something i don;t need to replace.

 

that looks like the right one to me