Installed new spark plugs and wires now throwing a p401 code(egr)???

[Deleted member 365508]

I just got finished installing new spark plugs (NGK Laser Platinum) and NGK Wires on my 2010 Ex 4.0 v6 4x4 on Thursday. Now I am getting a p401 code which is egr valve. When I pulled the old plugs out they were all gapped/worn past .060. Looks about like .070. My question is how was the ex running fine with no codes with such a big spark gap and when I put in the new items it decided to throw the p401 code. I don't belive the egr valve is bad but anything could happen. The code comes up every couple of days. My ex has 176k on it. Here are a couple of pics of the spark plug gap. All plugs are like this. The ring shown is at .060 in the gap. I plan on dropping by my mechanic to have a quick look. Any ideas?

 

[Blackhawkxx]

Are you sure that you didn't knock or crack a vacuum line or wire when you were changing the parts?

 

[Deleted member 365508]

Are you sure that you didn't knock or crack a vacuum line or wire when you were changing the parts?

Thanks for replying.. Pretty sure. No wires or vacuum lines near the spark plugs. Did go by and asked my mechanic about it and it happened to pop the code going there. It actually is an EGR air flow restriction code so it might just be a clogged pickup tube from the exhaust or a clogged air flow in the EGR valve. I put some Sea Foam cleaner in it to see if it will help otherwise I'll clean the pickup tube and valve this weekend. I'll report the results after this weekend

 

[Deleted member 365508]

Update, had to replace the egr valve to get rid of code.

 

[Blackhawkxx]

Update, had to replace the egr valve to get rid of code.

Sometimes things go bad at a really unfortunate time which makes one believe there is a connection. Thanks for letting us know how it turned out and congrats on getting it fixed.

 

[94Eddie]

This won't be your last run in with "sympathetic repairs." As the miles rack up it seems at times that one repair caused another failure. This does happen sometimes but most times it is just bad timing.

 

[Deleted member 365508]

This won't be your last run in with "sympathetic repairs." As the miles rack up it seems at times that one repair caused another failure. This does happen sometimes but most times it is just bad timing.

I believe you, now I have a p2195 code (O2 sensor stuck lean on bank 1 sensor 1) and the p0401 came back. Maybe dpfe is bad? Could the new spark plugs and wires be causing all the problems? Didn't have any codes until I decided to start to give it a tune up (plugs, wires and oil change so far). Now I'm thinking about not doing anything else to it because of any other potential gremlins waiting to show up. It's just frustrating. It's like opening up a can of worms. Oh and I hate Mondays. Maybe I should just replace the dpfe and all O2 sensors since it has high mileage.

 

[94Eddie]

I believe you, now I have a p2195 code (O2 sensor stuck lean on bank 1 sensor 1) and the p0401 came back. Maybe dpfe is bad? Could the new spark plugs and wires be causing all the problems? Didn't have any codes until I decided to start to give it a tune up (plugs, wires and oil change so far). Now I'm thinking about not doing anything else to it because of any other potential gremlins waiting to show up. It's just frustrating. It's like opening up a can of worms. Oh and I hate Mondays. Maybe I should just replace the dpfe and all O2 sensors since it has high mileage.

I can see where there could be a link. The old, worn plugs may have not been igniting all the fuel in the combustion chamber efficiently and the exhaust was running rich. This could mask a bad O2 sensor. When the new plugs and wires were installed the exhaust was now right and the bad O2 sensor now sees the exhaust being lean. I think getting the vehicle running right is the best course of action. Not doing maintenance will bite you hard at some point. Getting some good data logging done is probably in order or you might just be replacing parts until you stumble across the problem. A person with a good diagnostic computer can pinpoint about any problem if they know how to use it properly.

 

[Deleted member 365508]

As far as I can tell I guess my dpfe sensor is built onto the egr valve?

 

[94Eddie]

As far as I can tell I guess my dpfe sensor is built onto the egr valve?

I don't know the 4.0L V6 well enough to give you an answer. Someone here will chime in and let you know.

 

[Deleted member 365508]

I was just thinking, would a engine treatment like Seafoamfor High Mileage help or hurt. It's a little late now but I added that when I had a full tank of gas and now I'm down to a quarter.

Thanks 94Eddie for trying to help, and others also.

 

[94Eddie]

I was just thinking, would a engine treatment like Seafoamfor High Mileage help or hurt. It's a little late now but I added that when I had a full tank of gas and now I'm down to a quarter.

Thanks 94Eddie for trying to help, and others also.

For the last 300 miles of every third oil change I run Seafoam in the the engine oil. It does a good job of removing oil deposits. I don't put it in the gas tank all that often but it doesn't hurt to do it. Look on YouTube for some videos regarding fuel additives.

 

[Explorer75]

I believe you, now I have a p2195 code (O2 sensor stuck lean on bank 1 sensor 1) and the p0401 came back. Maybe dpfe is bad? Could the new spark plugs and wires be causing all the problems? Didn't have any codes until I decided to start to give it a tune up (plugs, wires and oil change so far). Now I'm thinking about not doing anything else to it because of any other potential gremlins waiting to show up. It's just frustrating. It's like opening up a can of worms. Oh and I hate Mondays. Maybe I should just replace the dpfe and all O2 sensors since it has high mileage.

When I had my 2010 V6 something very similar happened. No tune up involved, thou. First I got the EGR code, changed the EGR, it came back with a Evap code, changed that also, both came back. Dealer checked the lines, said bad PCM. It was a bad PCM. After PCM replacement all codes disappeared.
Before you consider the PCM, are all the parts you used Original Motorcraft? did you try and go fancy and used other spark plugs than the SP412?

 

[Deleted member 365508]

When I had my 2010 V6 something very similar happened. No tune up involved, thou. First I got the EGR code, changed the EGR, it came back with a Evap code, changed that also, both came back. Dealer checked the lines, said bad PCM. It was a bad PCM. After PCM replacement all codes disappeared.
Before you consider the PCM, are all the parts you used Original Motorcraft? did you try and go fancy and used other spark plugs than the SP412?

I used motorcraft part on egr valve but used ngk for plugs and wires. Plugs were about .070 on gap on the ones I removed, well worn. I think Blackhawkxx was on to something about a vacuum leak. I am going to have a smoke test done on the vacuum lines to see if there are any leaks. Just checked for codes since CEL came on and still have p0401 but now has p0455. Did some research and a vacuum leak dealing with the egr could produce that code. I did fix the p2195 by cleaning the mass air flow sensor though. Thanks for the suggestion as I will keep that in mind.

 

[Explorer75]

I used motorcraft part on egr valve but used ngk for plugs and wires. Plugs were about .070 on gap on the ones I removed, well worn. I think Blackhawkxx was on to something about a vacuum leak. I am going to have a smoke test done on the vacuum lines to see if there are any leaks. Just checked for codes since CEL came on and still have p0401 but now has p0455. Did some research and a vacuum leak dealing with the egr could produce that code. I did fix the p2195 by cleaning the mass air flow sensor though. Thanks for the suggestion as I will keep that in mind.

I strongly suggest you install original motorcraft plugs and wires.

 

[Deleted member 365508]

UPDATE on P0401 and P0455 codes
OK, so just to catch up on some things that has happened. I installed new plugs, wires and coil (NGK Brand on all of it). Afterwards I have been fighting a P0401 (EGR) code popping up about once a week. I also had added a locking cap on the gas filler neck also, later on this. I replaced the EGR valve with Motorcraft Brand. Still the code popped up. I did a vacuum leak check, no leaks and I got frustrated. I decided to wait for warmer weather and to let my frustration go. About 2 months ago I replaced the sparkplugs with Motorcraft Brand. Still got the code coming up. The OBDII scanner I was using ihas 3 colored lights green is all good, yellow is potential code and red is code needs attention. Every time I reset the P0401 code and check the next day it was always yellow (red when code was present). I replaced the NGK coil with the one that was on it originally about a week ago (I kept it and the wires just in case I might have needed them). I just checked for codes (no CEL yet) fully expecting to see the yellow light to be on indicating a possible code coming. But to my surprise it was green. The last time I seen that color was before I did the small tune up. So I want to say thank you to 94Eddie and especially Explorer75. For trying to help a hard headed person. And if anybody else has something similar happen to them I would definitely put Motorcraft parts on to save you any headaches like what I was dealing with. There was a P0455 code dealing with the fuel filler neck. I have also removed the locking cap to see if that code is eliminated. Again though thank you for the advice Explorer75 and 94Eddie.

 

[Deleted member 365508]

I'm not saying this will resolve all problems, but it might help.