2002 TBird P0401 code

[BigSteve]

After replacing the EGR, the DPFE, MAF, and IAT, I still get this code. I cleared the EGR line to the exhaust, cleared other hoses and checked the vacuum line from the EGR and found it to hold vacuum. There are not any catalytic odors. I cannot figure it out. Otherwise, the car runs spectacularly. I cannot shake the code. Any ideas? Also, I live in Tallahassee, can someone recommend a reputable and Thunderbird or Lincoln ls knowledgeable service department in the southeast? I do not trust the local places here. Thank you.
Steve

This page contains affiliate links for which I may be compensated. As an eBay Partner, and Amazon Associate I may be compensated if you make a purchase at no cost to you.

 

[biddle]

 

[Anthony C]

Wrap a damp rag around the EGR solenoid to prevent air from entering. That will force the EGR valve to open. The engine will run rough indicating good flow. Your DPFE voltage should change or rise to 4 volts. If the voltage does not change as you already know that would indicate a bad DPFE. If you unplug the DPFE and you will get a reading of 5 volts The wiring is good. This will confirm the DPFE sensor needs to be replaced.
But If you changed out all the components ...... You may just have clogged passages in the throttle body ......
On my truck for example the EGR tube was completely clogged.

 

[BigSteve]

OK, I cleaned everything out and all looks shiny and new and I STILL have the code.

 

[Anthony C]

You need to trouble shoot it .... What voltage are you getting ?
Did you disable the EGR solenoid?

 

[BigSteve]

It is a vacuum only operated EGR. This is the second one I have installed. It holds vacuum.

 

[Anthony C]

OK .... so you need to apply vacuum to that puppy ...... then observe how the engine reacts.
Do you have a hand vacuum pump\?
If so you need to apply vacuum to the EGR and allow to to open. The engine should almost stall out. If the engine continues to run ..... a little rough There may be a clog in the intake manifold or..... the EGR tube running from the EGR to the exhaust manifold. Thats the first step...
Im still thinking ...there is a clog in the system or the Solenoid is not working keeping in mind the parts you replaced.
Yes ...its very frustrating .....I know all about it ...

 

[Anthony C]

This is a 4.6 intake .......notice the carbon build up that leads to the EGR . I use my shop vac and a small screwdtiver, wire drill bit, whatever works ...to clean that out .

 

[BigSteve]

This is a 4.6 intake .......notice the carbon build up that leads to the EGR . I use my shop vac and a small screwdtiver, wire drill bit, whatever works ...to clean that out .

It is the 3.9L.

 

[BigSteve]

OK .... so you need to apply vacuum to that puppy ...... then observe how the engine reacts.
Do you have a hand vacuum pump\?
If so you need to apply vacuum to the EGR and allow to to open. The engine should almost stall out. If the engine continues to run ..... a little rough There may be a clog in the intake manifold or..... the EGR tube running from the EGR to the exhaust manifold. Thats the first step...
Im still thinking ...there is a clog in the system or the Solenoid is not working keeping in mind the parts you replaced.
Yes ...its very frustrating .....I know all about it ...

I will do that with the vacuum. I can attest that the elenty of exhaust which came out. NO clog. The issue must be in the intake manifold.

 

[Anthony C]

Yes it seems the clog must be there or behind it ....you did everything else. and Yes I know it is the 3.9 ... I dont have a photo..
Wow ... they dont make parts for this car .....? Very limited...

 

[Anthony C]

 

[Anthony C]

Is this your configuration?

 

[Anthony C]

I suspect the clog (in red) is between the throttle plate and the EGR. and or Inside the EGR supply tube (yellow). I believe this is a 2002 3.9.

 

[BigSteve]

Is this your configuration?

Yes. This is what I have.

 

[BigSteve]

Fixed. Pulled the egr and realized how easy the bracket which the egr is mounted was easy to remove. Pulled the bracket and could see the egr port. Probably cobstricted ny 40% from new. Cleaned it and reibstalked everything. I am sure rhis was the issue. Thanks.

 

[Anthony C]

Great news !!

 

[BigSteve]

It is disappointing to report a big thumbs down on the P0401. After a meticulous ckeaning if the egr port, the dreaded P0401 reared its ugly head again. I am at a loss as what to do next.

 

[Anthony C]

The information I posted above is incorrect (Wrap a damp rag around the EGR solenoid to prevent air from entering). It should read .... you need to apply vacuum to the EGR and allow to to open. Pull the Vacuum plug from the EGR solenoid and using another piece of vacuum line connect it to the EGR forcing it to open at the same time increase the RPMs and read the voltage to the DPFE.

 

[BigSteve]

ok